The blast hit buses carrying Shia residents as they waited to cross from rebel into government territory in an evacuation deal between warring sides.

The death toll from a bomb blast on a crowded Syrian bus convoy outside Aleppo on Saturday reached at least 112 people, the Syrian Observatory for Human Rights monitoring group said.

The dead included 109 people from Foua and Kfarya, among them 68 children and 13 women.

Syrian rescue workers the Civil Defence said that they had carted away at least 100 bodies from the site of the blast, which hit buses carrying Shia residents as they waited to cross from rebel into government territory in an evacuation deal between warring sides.

The British-based Observatory reported its new toll early on Sunday and said the number was expected to rise.

A stalled population transfer resumed on Saturday after the deadly explosion killed children, government supporters and opposition fighters, at an evacuation point adding new urgency to the widely criticized operation.

The blast ripped through a bus depot in the al-Rashideen area where thousands of government loyalists evacuated the day before waited restlessly for hours, as opposition fighters guarded the area while negotiators bickered over the completion of the transfer deal. Only metres away, hundreds of evacuees from pro-rebels areas also loitered in a walled-off parking lot, guarded by government troops.

Footage from the scene showed bodies, including those of fighters, lying alongside buses, some of which were charred and others gutted from the blast. Personal belongings could be seen dangling out of the windows. Fires raged from a number of vehicles as rescuers struggled to put them out.

The scenes were the last in the unyielding bloodshed Syrians are living through. Earlier this month, at least 89 people were killed in a chemical attack as children foaming at the mouth and adults gasping for last breath were also caught on camera.

The bloody mayhem that followed the Saturday attack only deepened the resentment of the transfer criticized as population engineering. It also reflected the chaos surrounding negotiations between the warring parties. The United Nations did not oversee the transfer deal of the villages of Foua and Kfraya, besieged by the rebels, and Madaya and Zabadani, encircled by the government.

No one claimed responsibility for the attack but pro-government media and the opposition exchanged accusations, each pointing to foreign interference or conspiracies undermining the deal.

State TV al-Ikhbariya said the attack was the result of a car bomb carrying food aid to be delivered to the evacuees in the rebel-held area ostensibly crisps for the children and accused rebel groups of carrying it out. A TV broadcaster from the area said, “There can be no life with the terrorist groups.”

“I know nothing of my family. I can’t find them,” said a woman who appeared on al-Ikhbariya, weeping outside the state hospital in Aleppo where the wounded were transported.

Ahrar al-Sham, the rebel group that negotiated the deal, denounced the “cowardly” attack, saying a number of opposition fighters as well as government supporters were killed in the attack. The group said the attack only serves to deflect the attention from government “crimes” and said it was ready to cooperate with an international probe to determine who did it.

Yasser Abdelatif, a media official for Ahrar al-Sham, said about 30 rebel gunmen were killed in the blast. He accused the government or extremist rebel groups of orchestrating the attack to discredit the opposition.

The Syrian Civil Defence in Aleppo province, also known as the White Helmets, said their volunteers pulled at least 100 bodies from the site of the explosion. White Helmets member Ibrahim Alhaj said the 100 fatalities documented by the rescuers included many children and women, as well as fighters.

U.N. Secretary-General Antonio Guterres condemned the attack on Saturday in a statement from his spokesman Stephane Dujarric, and called on all parties “to ensure the safety and security of those waiting to be evacuated.”

“Those responsible for today’s attack must be brought to justice,” the statement added.

The coordinated evacuations delivered war-weary fighters and residents from two years of siege and hunger, but moved Syria closer to a division of its national population by loyalty and sect.

The evacuees from Madaya headed to rebel-held Idlib, west of Aleppo. After the blast, evacuees from opposition areas pleaded for protection fearing revenge attacks.

Syrian state TV blamed the rebels for obstructing the deal.

An opposition representative, Ali Diab, accused the government side of violating the terms of the agreement, by evacuating fewer armed men than agreed to from the pro-government areas.