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The Iraqi city of Falluja is once again in the cross hairs

Iraqi operation underway to retake Sunni-dominated province of Anbar from ISIS

Falluja was the scene of two of ugliest battles for U.S. troops during Iraq War

CNN  — 

The black flag of ISIS has flown for more than a year in Falluja, an Iraqi city that has repeatedly served as a stronghold for insurgents over the years.

At least three offensives – two of the ugliest battles for U.S. troops during the Iraq War, and an Iraqi offensive last year – appear to have changed little in the long run.

Now, Falluja is once again in the cross hairs.

Iraqi forces have begun an operation to retake the Sunni-dominated province of Anbar from ISIS. Falluja and the provincial capital, Ramadi, are two strategic Anbar cities currently in the hands of the militant group.

Iraqi warplanes and artillery have bombarded Falluja and surrounding villages in recent days, killing more than 30 people, according to witnesses inside the city. Iraq’s anti-ISIS operation in Anbar includes Shiite militias, whose presence has fanned fears of sectarian conflict.

Here’s a recap of some of the previous major efforts to drive insurgents out of Falluja:

The First Battle of Falluja

On March 31, 2004, four American security contractors were killed in an ambush in Falluja. Shocking images of the Americans’ charred, mutilated bodies strung up from a bridge prompted outrage in the West.

The Bush administration put pressure on U.S. military officials to launch an offensive in Falluja despite protests from Marine generals that “a large-scale operation would send the wrong message, unnecessarily endanger civilians, and ultimately fail to achieve the primary objective of locating the individuals responsible for the murders,” according to a study by Marine Corps historians.

Their objections were overruled, and in early April, the Marines were sent in. American forces had to deal with fierce resistance from insurgents taking cover in mosques and other buildings as well as political pressure over the mounting civilian death toll.

The offensive also “galvanized the disparate Sunni insurgent groups into loose cooperation for the first time, and the fighting spread to other cities such as Ramadi,” said a study from the U.S. Army’s Center of Military History.

The offensive was suspended after less than a week. Shortly afterward, the Marines handed over responsibility for security to “a makeshift Iraqi force” known as the Falluja Brigade that “proved ineffective and short lived,” according to the Center of Military History study.

The Second Battle of Falluja

The resulting security vacuum in Falluja coupled with the public relations victory of having weathered the aborted American attack helped the militant groups there to thrive, including al Qaeda in Iraq, the forerunner of ISIS.

Both sides had plenty of time to prepare for the major U.S. offensive to drive the insurgents out, named Operation Phantom Fury. It began on November 8, 2004, and resulted in some of the hardest, bloodiest warfare American troops had experienced since Vietnam.

“The combat came down to five yards in a flak jacket. It was seeing the whites of their eyes,” Adam Mathes, a former Marine, told CNN last year.

The Marines went house to house, hunting down jihadists.

“It was an individual fight, man to man with spider holes where guys would pop out of,” Col. Michael Regner, operations officer for the First Marine Expeditionary Force, told The New York Times at the time. “If you weren’t streetwise – and you got streetwise about an hour into this operation – you’d find yourself as a casualty.”

The weeks-long operation ultimately succeeded in clearing out the insurgents, but it left Falluja a city of smoldering ruins. Reconstruction would take years.

The Sunni Awakening

The hard-fought victory brought no guarantee that al Qaeda and other jihadist groups wouldn’t return to Falluja. Attacks continued in and around the city for years.

The change that did the most to turn the tide against the insurgents came from the Sunni tribes in Anbar. From late 2006 onward, they rebelled against al Qaeda in a movement known as the Sunni Awakening.

“What turned it around was the local population deciding to reject al Qaeda,” then-Army Gen. David Petraeus told CBS in 2007.

The Awakening was bolstered by the large increase in U.S. troop levels in 2007. In May of that year, a U.S. commander described Falluja as “an economically strong and flourishing city.”

The return of the jihadists

By early last year, the Americans were long gone, and many Sunni tribespeople in Anbar had become increasingly disillusioned with Iraqi’s Shiite-dominated government in Baghdad.

ISIS fighters seized control of the city in January, exploiting the tensions between the tribes and Baghdad as well as the weakness of Iraqi security forces.

Four months later, the Iraqi government announced a large-scale operation to retake Falluja. But it failed to dislodge the militant group.

Like the Americans before them, the Iraqi forces found themselves facing criticism from human rights groups for causing civilian casualties in Falluja.

ISIS, which has eagerly publicized many of its atrocities, opened the gates of Falluja Dam in an effort to counter an Iraqi military advance, flooding numerous villages in the process.

For Americans who fought against ISIS’ predecessor in Falluja in 2004, seeing it back in the hands of jihadists was hard.

“We gave a lot, spilled blood, lost friends, invested a lot of our young adulthood to that city,” Mathes told CNN.