ALEPPO, Syria — Evacuation buses preparing to enter the besieged Syrian villages of al-Foua and Kefraya were attacked and burned, in Idlib province on Sunday, according to the Syrian State News Agency.

It comes as the evacuation operation was due to resume after being stopped on Friday.

NBC News Chief Global Correspondent Bill Neely, who is on the ground in Syria, said the burned-out buses had been set to rescue 4,000 people trapped in the two villages.

Neely saw unverified footage of a man identifying himself as a rebel shouting "Allahu akbar...we have succeeded in burning the buses that came to take those Shia away. We'll burn any more buses that come."

Syrian Organization for Human Rights said six buses were burned.

Local sources said the buses were set on fire by rebels, unhappy that besieged civilians were to be evacuated from the villages. The villages are Shi-ite, pro-Assad villages besieged by rebels.

Elsewhere in Ramouseh, buses were lined up with ambulances and U.N. vehicles, ready to enter east Aleppo to resume the evacuations there.

A man rides past burning buses while en route to evacuate ill and injured people from the besieged Syrian villages of al-Foua and Kefraya

The buses were yet to move at dusk on Sunday and it was unclear what time they would be able to begin any evacuations of people from the battered city.

The Aleppo evacuation was suspended Friday after a report of shooting at a crossing point into the enclave by both sides of the conflict. Thousands were evacuated before the process was suspended.

An amateur video posted online by opposition activists Friday showed scores of men, women and children running away from a crossing point for fear of being shot at. The video appeared genuine and corresponded to other reporting of the events by The Associated Press.