More than 100 people were killed when a car bomb exploded near buses evacuating Syrians outside of Aleppo on Saturday, rescue services say.

The explosion Saturday hit an evacuation point south of Aleppo city where dozens of buses have been parked for over 30 hours as a much criticized population transfer deal stalled.

In footage aired on Syrian TV, bodies, including fighters, were seen lying alongside buses, some of which were charred and others gutted from the blast. Personal belongings could be seen dangling out of the windows. The state TV channel said the car was carrying food aid but a rebel spokesman said the car had been parked in the area and abandoned.

The explosion hit the Rashideen area, a rebel-controlled district outside Aleppo city where evacuation buses carrying nearly 5,000 people from the northern rebel-besieged villages of Foua and Kfraya were stuck, causing a huge plume of black smoke. Residents from the two villages had been evacuated Friday, along with more than 2,000 from Madaya, an opposition-held town outside of Damascus besieged by government forces.

A senior rebel leader said 20 fighters who guarded the buses were killed as well as dozens of passengers. He spoke on the condition of anonymity because he was not authorized to speak to the media. Yasser Abdellatif, a member of the powerful Ahrar al-Sham group which negotiated the deal, said at least 30 rebels were killed in the explosion.

Prior to the blast, Syrian Red Crescent teams had distributed meals to the restless evacuees, stuck in limbo after having left their homes over 30 hours earlier. Many were already voicing their dissatisfaction with the wait.

"The people are restless and the situation is disastrous," said Ahmed Afandar, a resident evacuated from his the opposition area near Madaya. "All these thousands of people are stuck in less than half a kilometer (500 yards)." He said the area was walled off from all sides and there were no restrooms.

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 rebels disagreed over the number of gunmen to be evacuated, the buses were left stuck at two separate parts, but adjacent parts of the city.

The Associated Press contributed to this report.