Story highlights

Hundreds have been killed in Aleppo in recent days, opposition group says

Doctors operate while standing in pools of blood covering the white floors

A barrel bomb assault on the rebel-held city began more than a week ago

CNN  — 

Overwhelmed doctors frantically scurried over the weekend to help scores of patients left “dying on the floor” amid a punishing air assault on the northern Syrian city of Aleppo.

“There was a big massacre today,” Dr. Ammar Zakaria told CNN via Skype on Sunday from the country’s largest city and rebel stronghold. “We were treating shrapnel wounds, deep abdominal and brain injuries. I just lost count of the amputations.”

The Syrian government continued to relentlessly fire on rebel-held sections of the city after days of continued air raids.

The city has been targeted for more than a week by helicopters carrying so-called barrel bombs – drums packed with explosives and shrapnel. The bombs can level entire buildings with one hit.

“A lot of victims died before arriving to the hospital. Many were inside the hospital, and we didn’t have the resources to help all the cases,” added Zakaria, detailing the bloody aftermath. “We didn’t have enough beds to help them all. People were dying on the floor.”

With medical supplies spread thin, each anxiety-filled second was spent suturing the fine line between life and death.

Images taken by Zakaria show a mangled ambulance stopped in its path and doctors operating in pools of blood, watching children cling to their last breath through a breathing tube.

“In Aleppo, there is a huge influx of wounded in local hospitals … less and less security and more bombing on civilian areas,” Simon Schorno, Syria spokesman for the International Committee of the Red Cross, told CNN by phone from Damascus.

The Syrian government said the operations are targeting “terrorist groups” in neighborhoods of Aleppo, saying “scores of terrorists were killed and others were wounded,” according to the state-run Syrian Arab News Agency.

Hundreds have been killed since the bombing began. At least half a million people have been wounded across the country, and millions remain displaced and tens of thousands detained, according to the ICRC.

On Sunday alone, 166 people were killed across the country, 92 in Aleppo, according to the opposition Local Coordination Committees in Syria. CNN cannot independently verify daily death tolls, but the United Nations says more than 100,000 people have been killed in Syria since 2011.

“Supplies of food and other basic necessities are running dangerously short, especially in besieged areas,” said Magne Barth, head of the ICRC delegation in Syria.

Schorno described difficult conditions for delivering aid.

“We don’t get the necessary authorizations to get in. The government needs to green-light our movements through the checkpoints and we have to go in on foot, and we cannot do that under current conditions,” Schorno added.

The death toll continues to mount as misery for the millions of displaced is exacerbated by the record cold temperatures across the Middle East.

The hospital has become home for many Syrian doctors like Zakaria.

“We live in the hospitals because we cannot expect the timing of the shelling; we have to be ready all the time.”