At least 39 people were killed Saturday in a suspected suicide explosion that hit near busses carrying people evacuated from a besieged area of government loyalists, Syrian TV reported. A war monitor puts the death toll at 24 in the area controlled by opposition fighters.

The explosion Saturday was caused by a car bomb, according to Syrian TV and the opposition Britain-based Syrian Observatory for Human Rights, causing massive destruction. In footage aired on Syrian TV, bodies were strewn outside busses, including fighters. Some busses were charred and others gutted from the explosion as belongings hanged out of windows.

The explosion hit an area where busses carrying nearly 5,000 people from Foua and Kfraya, villages in northern Syria that have been besieged by militants. They were evacuated Friday, along with more than 2,000 from Madaya, a town outside of Damascus which was besieged by government forces.

The busses carrying nearly 5,000 pro-government evacuees have been stuck in an area on the edge of Aleppo city, as a much criticised population transfer deal stalls. According to the deal, more than 2,000 residents, activists and gunmen from areas besieged by government forces were also evacuated. But as the government and militants disagreed over the number of gunmen to be evacuated, the busses were left stuck at two separate parts, but adjacent parts of the city.

Activists and residents say thousands of Syrians evacuated from their besieged towns have spent the night on busses at an exchange point as a much criticised population transfer deal stalls.

Ahmed Afandar, a resident evacuated from his hometown near Madaya, says dozens of busses carrying children, women and men are not allowed to proceed toward militant-held Idlib as planned. He said it is not clear what hinders the completion of the evacuation.

Rami Abdurrahman, head of the Britain-based Syrian Observatory for Human Rights, says the Syrian government and militant who negotiated the deal have differed over the evacuation of gunmen from the towns.

A resident of Zabadani, another militant-held town to be evacuated, Amer Burhan says no evacuation has taken place from there.