The death toll in a suicide car bomb attack on buses carrying Syrians evacuated from two besieged government-held towns has risen to at least 112, a monitoring group said Sunday.

The Syrian Observatory for Human Rights said that 98 evacuees from the northern towns of Fuaa and Kafraya were killed when an explosives-laden vehicle hit their buses at a transit point west of Aleppo on Saturday.

It said the remainder of the dead were aid workers and rebels tasked with guarding the buses.

It warned the death toll may rise further as “hundreds” more were wounded in the blast.

Dozens of buses carrying several thousand refugees had been stuck by the roadside in the rebel-held town of Rashidin after leaving Fuaa and Kafraya on Friday under a deal reached between the government and opposition groups.

Fuaa and Kafraya have been under rebel siege for more than two years. As part of the deal, several hundred people including armed rebels will be transported out of Madaya and Zabadani, towns near Damascus, which are surrounded by pro-government forces.

Syrian rescue workers volunteering as first responders in rebel-controlled areas say at least 100 people were killed and 55 injured in a car bomb explosion that ripped through a makeshift bus depot in Aleppo province where evacuees were waiting to be transported to government-held areas.

The Syrian Civil Defense in Aleppo province, also known as the White Helmets, said its volunteers removed at least 100 bodies from the scene of the blast. The group said on Twitter that a car bomb caused the explosion.

Syrian state media put the death toll at 39, including civilians and rebel fighters. A rebel official said at least 30 of his fighters guarding evacuees died in the blast. ​President Bashar Assad’s government blamed the attack on rebels.

The British-based Syrian Observatory for Human Rights put the death toll at 43, but said it was expected to rise.

In footage aired on Syrian TV, bodies, including fighters, were seen lying alongside charred and destroyed buses. The channel said the car used in the bombing was carrying food aid but the rebels said the car had been parked in the area and abandoned.