Story highlights
- The CIA director said Monday ISIS members have "gone to school" on new ways to avoid authorities
- Earlier, President Obama's national security team suggested the threat remains greater in Europe
Antalya, Turkey (CNN)ISIS probably has plans for more attacks "in the pipeline," according to the head of the CIA, although President Barack Obama's national security team said over the weekend that the threat to Europe is greater than it is to the U.S.
"I certainly would not consider it a one-off event," said CIA Director John Brennan, speaking at a Center for Strategic and International Studies forum in Washington on Monday.
"It is clear to me that ISIL has an external agenda, that they are determined to carry out these types of attacks," he continued, using another term for ISIS. "This is not something that was done in a matter of days. This was carefully planned over the course I think of several months, in terms of making (sure) they had the operatives, the weapons and the explosives with the suicide belts."
He concluded, "And so I would anticipate this is not the only operation that ISIL has in the pipeline."
A forensic scientist works near a Paris cafe on Saturday, November 14, following a series of coordinated attacks in Paris the night before that killed scores of people. ISIS has claimed responsibility.
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Police are out in force November 14 near La Belle Equipe, one of the sites of the terror attacks.
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Forensic police search for evidence inside the Comptoir Voltaire cafe after the attacks.
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Shoes and a bloody shirt lie outside the Bataclan concert hall on November 14. Most of the fatalities occurred at the Bataclan in central Paris.
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Security forces evacuate people on Rue Oberkampf near the Bataclan concert hall early on November 14.
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Medics evacuate an injured woman on Boulevard des Filles du Calvaire near the Bataclan early on November 14.
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Police, firefighters and rescue workers secure the area near the Bataclan concert hall on November 14.
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A man with blood on his shirt talks on the phone on November 14. He is next to the Bataclan theater, where gunmen shot concertgoers and held hostages until police raided the building.
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Police officers patrol the area around Notre Dame cathedral in Paris on November 14.
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Police officers patrol Paris' Saint-German neighborhood on November 14.
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Victims of the shooting at the Bataclan concert venue in central Paris are evacuated to receive medical treatment on November 14.
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A woman is evacuated from the Bataclan theater early on November 14.
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Forensics are working in the street of Paris after the terrorist attack on Friday, November 13. The words "horror," "massacre" and "war" peppered the front pages of the country's newspapers, conveying the shell-shocked mood.
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Rescuers evacuate an injured person near the Stade de France, one of several sites of attacks November 13 in Paris. Thousands of fans were watching a soccer match between France and Germany when the attacks occurred.
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A survivor of the terrorist attack in the Bataclan is assisted following terror attacks, November 13. The violence at the Bataclan, which involved a hostage-taking, resulted in the highest number of casualties of all the attacks.
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Spectators invade the pitch of the Stade de France stadium after the international friendly soccer match between France and Germany in Saint-Denis.
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Spectators embrace each other as they stand on the playing field of the Stade de France stadium at the end of a soccer match between France and Germany in Saint-Denis, outside Paris, on November 13.
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A body, covered by a sheet, is seen on the sidewalk outside the Bataclan theater.
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Rescuers evacuate an injured person on Boulevard des Filles du Calvaire, close to the Bataclan concert hall in central Paris.
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Wounded people are evacuated outside the scene of a hostage situation at the Bataclan theater in Paris on November 13.
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A medic tends to a wounded man following the attacks near the Boulevard des Filles du Calvaire.
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A woman walks past police and firefighters in the Oberkampf area of Paris.
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A riot police officer stands by an ambulance near the Bataclan concert hall in central Paris.
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Wounded people are evacuated outside the Bataclan concert hall.
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Police secure the Stade de France in Saint-Denis, north of Paris, following explosions during the soccer match between France and Germany.
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A wounded man is evacuated from the Stade de France in Saint-Denis, outside Paris.
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Spectators gather on the field of the Stade de France after the attacks. Explosions were heard during the soccer match between France and Germany.
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French security forces rush in as people are evacuated in the area of Rue Bichat in the 10th District of Paris.
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People leave the Stade de France after explosions were heard near the stadium during a soccer match between France and Germany on Friday. Paris Deputy Mayor Patrick Klugman told CNN President Francois Hollande was at the match and was evacuated at halftime.
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Victims lay on the pavement outside a Paris restaurant.
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Rescue workers and medics tend to victims at the scene of one of the shootings, a restaurant in the 10th District. Attackers reportedly used AK-47 automatic weapons in separate attacks across Paris, and there were explosions at the Stade de France.
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French security forces move people in the area of Rue Bichat in the 10th District. A witness told BFMTV that firefighters were on the scene to treat the injured.
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ISIS members have worked hard to learn new ways to conceal their tactics from Western law enforcement entities, according to Brennan.
"There has been a significant increase in the operational security in the number of these operatives in these terrorist networks because they have gone to school on what it is they need to do to keep their activities concealed from the authorities," he said.
The comments from Brennan came the day after members of the President's national security team said that while ISIS certainly has the ambition to launch similar attacks on U.S. shores, the capability is not great..
Deputy National Security Adviser Ben Rhodes told reporters that one big difference between the situation in Europe and that in the U.S. is that "thousands" of fighters have traveled to Syria and then returned to Europe. The number being tracked in America is far smaller -- around 40, according to an estimate by Director of National Intelligence James Clapper earlier this year.
Clapper added that not all of those ISIS joiners were necessarily fighting -- some might have served other roles for the terrorist group, such as first aid -- and he knew of no terrorist plots that any of those returning have been involved in once back in the U.S.
Rhodes said that ISIS has found more utility in trying to recruit or motivate sympathizers in America online from abroad.
Obam adviser Ben Rhodes on Paris attacks 07:09
A top FBI counterterrorism official told Congress this year that "hundreds, maybe thousands" of people in the U.S. follow ISIS online. And this year alone, at least 49 alleged ISIS "supporters" in America have been charged with related crimes. The largest number of those were in New York.
An ISIS-inspired plot in Garland, Texas, in May, in which two men with body armor and assault rifles opened fire outside an art contest in which participants drew pictures of the prophet Mohammed, was thwarted by a security officer who shot and killed both suspects.
The FBI had been watching one of the suspects' online activity referencing the contest, and had warned police in Garland hours before the attack, though officials didn't know he was planning an attack, and weren't closely monitoring his physical whereabouts.
Following that attack, intelligence officials have said they are now doing more monitoring of "hundreds" of suspected ISIS supporters.
Rhodes emphasized Sunday there is currently "no specific, credible threat" of an attack being planned in the U.S., but vigilance among law enforcement is high.
Photos: The ISIS terror threat
Wounded passengers are treated following a suicide bombing at the Brussels Airport on March 22, 2016. The attacks on the airport and a subway killed 32 people and wounded more than 300. ISIS claims its "fighters" launched the attacks in the Belgian capital.
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Photos: The ISIS terror threat
Syrians gather at the site of a double car bomb attack in the Al-Zahraa neighborhood of the Homs, Syria, on February 21, 2016. Multiple attacks in Homs and southern Damascus kill at least 122 and injure scores, according to the state-run SANA news agency. ISIS claimed responsibility.
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Photos: The ISIS terror threat
Syrian pro-government forces gather at the site of a deadly triple bombing Sunday, January 31, in the Damascus suburb of Sayeda Zeynab. ISIS claimed responsibility for the attack, according to a statement circulating online from supporters of the terrorist group.
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Photos: The ISIS terror threat
Yemenis check the scene of a car bomb attack Sunday, December 6, in Aden, Yemen. Aden Gov. Jaafar Saad and six bodyguards died in the attack, for which the terror group ISIS claimed responsibility.
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Photos: The ISIS terror threat
Investigators check the scene of a mosque attack Friday, November 27, in northern Bangladesh's Bogra district. ISIS has claimed responsibility for the attack that left at least one person dead and three more wounded.
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Photos: The ISIS terror threat
Wounded people are helped outside the Bataclan concert hall in Paris following a series of coordinated attacks in the city on Friday, November 13. The militant group ISIS claimed responsibility for the attacks, which killed at least 130 people and wounded hundreds more.
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Photos: The ISIS terror threat
Emergency personnel and civilians gather at the site of a twin suicide bombing in Beirut, Lebanon, on Thursday, November 12. The bombings killed at least 43 people and wounded more than 200 more. ISIS appeared to claim responsibility in a statement posted on social media.
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Photos: The ISIS terror threat
Smoke rises over the northern Iraqi town of Sinjar on November 12. Kurdish Iraqi fighters, backed by a U.S.-led air campaign, retook the strategic town, which ISIS militants overran last year. ISIS wants to create an Islamic state across Sunni areas of Iraq and Syria.
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Photos: The ISIS terror threat
Syrian government troops walk inside the Kweiras air base on Wednesday, November 11, after they broke a siege imposed by ISIS militants.
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Photos: The ISIS terror threat
Members of the Egyptian military approach the wreckage of a Russian passenger plane Sunday, November 1, in Hassana, Egypt. The plane crashed the day before, killing all 224 people on board. ISIS claimed responsibility for downing the plane, but the group's claim wasn't immediately verified.
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Photos: The ISIS terror threat
An explosion rocks Kobani, Syria, during a reported car bomb attack by ISIS militants on Tuesday, October 20.
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Shiite fighters, fighting alongside Iraqi government forces, fire a rocket at ISIS militants as they advance toward the center of Baiji, Iraq, on Monday, October 19.
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Photos: The ISIS terror threat
Smoke rises above a damaged building in Ramadi, Iraq, following a coalition airstrike against ISIS positions on Saturday, August 15.
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Photos: The ISIS terror threat
Iraqi men look at damage following a bomb explosion that targeted a vegetable market in Baghdad on Thursday, August 13. ISIS claimed responsibility for the attack.
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Photos: The ISIS terror threat
In this image taken from social media, an ISIS fighter holds the group's flag after the militant group overran the Syrian town of al-Qaryatayn on Thursday, August 6, the London-based Syrian Observatory for Human Rights reported. ISIS uses modern tools such as social media to promote reactionary politics and religious fundamentalism. Fighters are destroying holy sites and valuable antiquities even as their leaders propagate a return to the early days of Islam.
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Photos: The ISIS terror threat
An ISIS fighter poses with spoils purportedly taken after capturing the Syrian town of al-Qaryatayn.
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Smoke rises as Iraqi security forces bomb ISIS positions in the eastern suburbs of Ramadi, Iraq, on August 6.
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Buildings reduced to piles of debris can be seen in the eastern suburbs of Ramadi on August 6.
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Photos: The ISIS terror threat
The governor of the Asir region in Saudi Arabia, Prince Faisal bin Khaled bin Abdulaziz, left, visits a man who was wounded in a suicide bombing attack on a mosque in Abha, Saudi Arabia, on August 6. ISIS claimed responsibility for the explosion, which killed at least 13 people and injured nine others.
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Photos: The ISIS terror threat
Saudi officials and investigators check the inside of the mosque on August 6.
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Photos: The ISIS terror threat
Mourners in Gaziantep, Turkey, grieve over a coffin Tuesday, July 21, during a funeral ceremony for the victims of a suspected ISIS suicide bomb attack. That bombing killed at least 31 people in Suruc, a Turkish town that borders Syria. Turkish authorities blamed ISIS for the attack.
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Photos: The ISIS terror threat
Protesters in Istanbul carry anti-ISIS banners and flags to show support for victims of the Suruc suicide blast during a demonstration on Monday, July 20.
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Photos: The ISIS terror threat
People in Ashmoun, Egypt, carry the coffin for 1st Lt. Mohammed Ashraf, who was killed when the ISIS militant group attacked Egyptian military checkpoints on Wednesday, July 1. At least 17 soldiers were reportedly killed, and 30 were injured.
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Photos: The ISIS terror threat
Syrians wait near the Turkish border during clashes between ISIS and Kurdish armed groups in Kobani, Syria, on Thursday, June 25. The photo was taken in Sanliurfa, Turkey. ISIS militants disguised as Kurdish security forces infiltrated Kobani on Thursday and killed "many civilians," said a spokesman for the Kurds in Kobani.
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Residents examine a damaged mosque after an Iraqi Air Force bombing in the ISIS-seized city of Falluja, Iraq, on Sunday, May 31. At least six were killed and nine others wounded during the bombing.
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People search through debris after an explosion at a Shiite mosque in Qatif, Saudi Arabia, on Friday, May 22. ISIS claimed responsibility for the attack, according to tweets from ISIS supporters, which included a formal statement from ISIS detailing the operation.
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Photos: The ISIS terror threat
Iraqi soldiers fire their weapons toward ISIS group positions in the Garma district, west of the Iraqi capital of Baghdad, on Sunday, April 26. Pro-government forces said they had recently made advances on areas held by Islamist jihadists.
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Photos: The ISIS terror threat
A member of Afghanistan's security forces stands at the site where a suicide bomber on a motorbike blew himself up in front of the Kabul Bank in Jalalabad, Afghanistan, on Saturday, April 18. ISIS claimed responsibility for the attack. The explosion killed at least 33 people and injured more than 100 others, a public health spokesman said.
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Photos: The ISIS terror threat
Iraqi counterterrorism forces patrol in Ramadi on April 18.
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Photos: The ISIS terror threat
Thousands of Iraqis cross a bridge over the Euphrates River to Baghdad as they flee Ramadi on Friday, April 17.
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Photos: The ISIS terror threat
Yazidis embrace after being released by ISIS south of Kirkuk, Iraq, on Wednesday, April 8. ISIS released more than 200 Yazidis, a minority group whose members were killed, captured and displaced when the Islamist terror organization overtook their towns in northern Iraq last summer, officials said.
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Photos: The ISIS terror threat
Kurdish Peshmerga forces help Yazidis as they arrive at a medical center in Altun Kupri, Iraq, on April 8.
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Photos: The ISIS terror threat
A Yazidi woman mourns for the death of her husband and children by ISIS after being released south of Kirkuk on April 8. ISIS is known for killing dozens of people at a time and carrying out public executions, crucifixions and other acts.
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Photos: The ISIS terror threat
People in Tikrit inspect what used to be a palace of former President Saddam Hussein on April 3.
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On April 1, Shiite militiamen celebrate the retaking of Tikrit, which had been under ISIS control since June. The push into Tikrit came days after U.S.-led airstrikes targeted ISIS bases around the city.
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Photos: The ISIS terror threat
Iraqi security forces launch a rocket against ISIS positions in Tikrit on Monday, March 30.
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The parents of 19-year-old Mohammed Musallam react at the family's home in the East Jerusalem Jewish settlement of Neve Yaakov on Tuesday, March 10. ISIS released a video purportedly showing a young boy executing Musallam, an Israeli citizen of Palestinian descent who ISIS claimed infiltrated the group in Syria to spy for the Jewish state. Musallam's family told CNN that he had no ties with the Mossad, Israel's spy agency, and had, in fact, been recruited by ISIS.
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Photos: The ISIS terror threat
Iraqi Shiite fighters cover their ears as a rocket is launched during a clash with ISIS militants in the town of Al-Alam, Iraq, on Monday, March 9.
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Photos: The ISIS terror threat
Displaced Assyrian women who fled their homes due to ISIS attacks pray at a church on the outskirts of Damascus, Syria, on Sunday, March 1. ISIS militants abducted at least 220 Assyrians in Syria.
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Photos: The ISIS terror threat
Safi al-Kasasbeh, right, receives condolences from tribal leaders at his home village near Karak, Jordan, on Wednesday, February 4. Al-Kasasbeh's son, Jordanian pilot Moath al-Kasasbeh, was burned alive in a video that was recently released by ISIS militants. Jordan is one of a handful of Middle Eastern nations taking part in the U.S.-led military coalition against ISIS.
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Photos: The ISIS terror threat
A Kurdish marksman looks over a destroyed area of Kobani on Friday, January 30, after the city had been liberated from the ISIS militant group. The Syrian city, also known as Ayn al-Arab, had been under assault by ISIS since mid-September.
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Kurdish people celebrate in Suruc, Turkey, near the Turkish-Syrian border, after ISIS militants were expelled from Kobani on Tuesday, January 27.
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Photos: The ISIS terror threat
Collapsed buildings are seen in Kobani on January 27 after Kurdish forces took control of the town from ISIS.
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Junko Ishido, mother of Japanese journalist Kenji Goto, reacts during a news conference in Tokyo on Friday, January 23. ISIS would later kill Goto and another Japanese hostage, Haruna Yukawa.
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Photos: The ISIS terror threat
ISIS militants are seen through a rifle's scope during clashes with Peshmerga fighters in Mosul, Iraq, on Wednesday, January 21.
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Photos: The ISIS terror threat
An elderly Yazidi man arrives in Kirkuk after being released by ISIS on Saturday, January 17. The militant group released about 200 Yazidis who were held captive for five months in Iraq. Almost all of the freed prisoners were in poor health and bore signs of abuse and neglect, Kurdish officials said.
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Photos: The ISIS terror threat
Smoke billows behind an ISIS sign during an Iraqi military operation to regain control of the town of Sadiyah, about 95 kilometers (60 miles) north of Baghdad, on Tuesday, November 25.
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Fighters from the Free Syrian Army and the Kurdish People's Protection Units join forces to fight ISIS in Kobani on Wednesday, November 19.
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A picture taken from Turkey shows smoke rising after ISIS militants fired mortar shells toward an area controlled by Syrian Kurdish fighters near Kobani on Monday, November 3.
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Iraqi special forces search a house in Jurf al-Sakhar, Iraq, on Thursday, October 30, after retaking the area from ISIS.
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ISIS militants stand near the site of an airstrike near the Turkey-Syria border on Thursday, October 23. The United States and several Arab nations have been bombing ISIS targets in Syria to take out the militant group's ability to command, train and resupply its fighters.
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Kurdish fighters walk to positions as they combat ISIS forces in Kobani on Sunday, October 19.
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Heavy smoke rises in Kobani following an airstrike by the U.S.-led coalition on October 18.
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Cundi Minaz, a female Kurdish fighter, is buried in a cemetery in the southeastern Turkish town of Suruc on Tuesday, October 14. Minaz was reportedly killed during clashes with ISIS militants in nearby Kobani.
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Kiymet Ergun, a Syrian Kurd, celebrates in Mursitpinar, Turkey, after an airstrike by the U.S.-led coalition in Kobani on Monday, October 13.
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Alleged ISIS militants stand next to an ISIS flag atop a hill in Kobani on Monday, October 6.
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A Kurdish Peshmerga soldier who was wounded in a battle with ISIS is wheeled to the Zakho Emergency Hospital in Duhuk, Iraq, on Tuesday, September 30.
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Syrian Kurds wait near a border crossing in Suruc as they wait to return to their homes in Kobani on Sunday, September 28.
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A elderly man is carried after crossing the Syria-Turkey border near Suruc on Saturday, September 20.
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A Kurdish Peshmerga fighter launches mortar shells toward ISIS militants in Zumar, Iraq, on Monday, September 15.
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Kurdish Peshmerga fighters fire at ISIS militant positions from their position on the top of Mount Zardak, east of Mosul, Iraq, on Tuesday, September 9.
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Displaced Iraqis receive clothes from a charity at a refugee camp near Feeshkhabour, Iraq, on Tuesday, August 19.
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Aziza Hamid, a 15-year-old Iraqi girl, cries for her father while she and some other Yazidi people are flown to safety Monday, August 11, after a dramatic rescue operation at Iraq's Mount Sinjar. A CNN crew was on the flight, which took diapers, milk, water and food to the site where as many as 70,000 people were trapped by ISIS. But only a few of them were able to fly back on the helicopter with the Iraqi Air Force and Kurdish Peshmerga fighters.
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Thousands of Yazidis are escorted to safety by Kurdish Peshmerga forces and a People's Protection Unit in Mosul on Saturday, August 9.
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Thousands of Yazidi and Christian people flee Mosul on Wednesday, August 6, after the latest wave of ISIS advances.
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A Baiji oil refinery burns after an alleged ISIS attack in northern Selahaddin, Iraq, on Thursday, July 31.
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A Syrian rebel fighter lies on a stretcher at a makeshift hospital in Douma, Syria, on Wednesday, July 9. He was reportedly injured while fighting ISIS militants.
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Children stand next to a burnt vehicle during clashes between Iraqi security forces and ISIS militants in Mosul on Tuesday, June 10.
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