Death Toll Mounts as Air Raids Target Aleppo for Third Day

Syrian aircraft pounded rebel-held areas of Aleppo for a third day Tuesday, with hospitals reportedly overwhelmed as more than 100 people have been killed in the bombing.

Two children were among at least 20 people killed in Aleppo on Tuesday, according to the Syrian Observatory for Human Rights, a Britain-based group that relies on activists and other witnesses on the ground in Syria.

Air strikes on rebel-held areas Sunday and Monday killed 86 people, including 32 children, the Observatory said.

Aleppo, Syria's second city and onetime commercial hub, emerged as a key front after a rebel offensive last year. The northern city is today split between regime and rebel-controlled enclaves.

An estimated 126,000 people have been killed in Syria's civil war, which erupted after a brutal crackdown on pro-democracy protests first held in March 2011.

International humanitarian organization Doctors Without Borders (MSF) corroborated reports that regime helicopters started dropping barrel bombs on Aleppo on Sunday.

In just two cases -- the targeting of a school and a roundabout where people wait for public transport -- "there were dozens of dead and injured people," MSF Syria coordinator Aitor Zabalgogeazkoa said.

"A dozen bodies were being lined up in front of three hospitals waiting to be recovered by the families."

"The hospitals in the area are overrun and are asking for medical supplies. We sent them immediately," Zabalgogeazkoa said.

Earlier, the Observatory and activists said the air force had been dropping barrels of explosives from both helicopters and fixed-wing aircraft.

Observatory director Rami Abdel Rahman said there was a "marked escalation" in attacks, and that "this type of intensive bombing over several days demonstrates the desire of the army to advance" on rebel-held areas.