At least eight children were killed Sunday in Syria when rockets struck a school in Aleppo, in a sixth straight day of airstrikes that included a barrel bomb that killed a family of six, Reuters reported.

A teacher was among the dead, the Associated Press reported.

The shelling killed at least eight children among 10 deaths in the Saria Hasoun School, bringing the death toll to about 300 since Tuesday, the start of one of the heaviest bombardments in the country’s six-year civil war.

Medics cited by Reuters said the al-Baytounji family had suffocated to death because of the barrel bomb, which fell at about midnight and reportedly was laced with chlorine gas.

The two medics identified the family in a film that was released online. The video showed the bodies of four children lying shoulder-to-shoulder on the floor, each showing blue lips and dark marks around their eyes.

The Syrian Observatory for Human Rights, however, which monitors the war, reportedly could not confirm that chlorine gas was used.

The Syrian government forces have used chlorine gas bombs – made by oil drums filled with high explosives and dropped from helicopters – at least three times during the war, the United Nations found, although government officials deny the charge.

At least 54 people were killed in bombing attacks on Saturday, and air strikes continued to hit several districts of eastern Aleppo on Sunday, the Observatory said.

On Friday alone, airstrikes hit four hospitals in east Aleppo, effectively rendering all hospitals in the enclave of 275,000 people out of service, according to the opposition's Aleppo Health Directorate and the World Health Organization.

Footage obtained by the Associated Press shows what appears to be a waiting room at the hospital as people milled about, including nurses in blue uniforms. The airstrike then hits, turning the room into a swirl of gray dust.  Debris is strewn around and part of the false ceiling collapses.

RUSSIA'S LONG-RANGE MISSILES STRIKE SYRIA

The civil war in Syria pits President Bashar Assad against mostly Sunni rebels.  Assad is backed by Russia’s air force, Iran and Shi’ite militias, while Sunni rebels are joined by groups supported by the  United State, Turkey and Gulf monarchies, according to the Reuters report.

The Syrian government on Sunday refused a U.N. proposal to grant the rebel-held eastern districts of Aleppo autonomy in order to restore calm to the war-torn city.

Foreign Minister Walid al-Moallem said the state's institutions "must be restored" across the city and the militants expelled.

At least 164 civilians have been killed since the government renewed its assault on the besieged enclave six days ago, according to the Britain-based Observatory.

The U.N. estimates 275,000 people are trapped inside. By Saturday, the government had damaged or destroyed every hospital in the east, according to the Syrian American Medical Society, which supports doctors and hospitals in Syria.

Rebels outside the city have meanwhile launched two unsuccessful offensives to break the government's siege and shelled the government-held western districts.

U.N. envoy Staffan de Mistura had proposed that the Syrian government grant eastern Aleppo autonomy in exchange for peace, and called on the estimated 900 Al Qaeda-linked militants in the east to depart to other rebel-held territory in Syria.

But al-Moallem refused the offer in a meeting with de Mistura in Damascus on Sunday. Addressing a press conference after the meeting, the foreign minister said restoring government rule was a matter of "national sovereignty." He said Damascus would not allow the people of eastern Aleppo to be "hostages to 6,000 gunmen."

The Associated Press contributed to this report.