BEIRUT - Activists say militants have burned at least five buses assigned to evacuate wounded and sick people from two villages in northern Syria. The incident could scuttle a wider deal that encompasses the evacuation of thousands of trapped rebel fighters and civilians from the last opposition foothold in east Aleppo.

The opposition’s Britain-based Syrian Observatory for Human Rights said Sunday that the al Qaeda affiliated Fatah al-Sham Front burned buses assigned to evacuate people from the rebel-besieged villages of Foua and Kfarya.

Hezbollah, the Lebanese militant group fighting alongside Syria’s government, said the buses were burned during fighting between the al-Qaeda-affiliated Fatah al-Sham Front and a rebel group that supported the evacuations.

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The Observatory says six buses were burned while Hezbollah’s media outlet put the number at five.

Syrian media said earlier Sunday that buses and ambulances were preparing to enter east Aleppo to resume evacuating rebels and civilians from the opposition’s remaining districts in the city.

Pro-government Al-Ikhbariya TV says Sunday that convoys were also preparing to evacuate over 2,000 wounded and sick residents from the northern Syrian villages of Foua and Kfarya , which are besieged by rebels. It’s not clear what will happen to that operation after the fighting there.

In Aleppo, English teacher Wissam Zarqa said families have been assigned bus numbers and are preparing to evacuate after pro-government forces halted operations on Friday.

The government’s side said it wanted simultaneous evacuations from Foua and Kfarya. Several thousand civilians evacuated Aleppo Thursday before the process was halted.

The U.N. Security Council will meet today to try to send observers to the besieged Syrian city of Aleppo in order to monitor evacuations and report on the protection of civilians, CBS News’ Pamela Falk reports.

Diplomats expect to vote on a French-sponsored U.N. Resolution that demands that all parties provide the UN with “safe, immediate and unimpeded access” to monitor evacuations from parts of Aleppo that are being bombed, as well as to monitor protection of civilians inside Aleppo.

The U.N. draft, seen by CBS News, states: “these evacuations must be conducted in accordance with international humanitarian law and principles and emphasizes that the evacuations of civilians must be voluntary and to final destinations of their choice, and protection must be provided to all civilians who choose or who have been forced to be evacuated and those who opt to remain in their homes.”

The Resolution also, “Calls on all parties to respect and protect all medical and humanitarian personnel, their means of transport and equipment, as well as hospitals and other medical facilities throughout the country.”

France’s U.N. ambassador, Francois Delattre, said the resolution’s goal is to avoid “mass atrocities” by Syrian forces, and especially militias, in eastern Aleppo, which is now defenseless following the defeat of rebel forces.

“Our goal is to avoid another or a new Srebrenica,” Delattre said, a reference to the massacre of nearly 8,000 Bosnian Muslims who sought protection in the U.N. safe haven of Srebrenica in 1995 during the Bosnian war.

Late Sunday, Russia proposed a rival U.N. resolution that would require Syrian government approval before the U.N. could deploy any monitors to eastern Aleppo to check on civilians. The Russian draft eliminates any U.N. monitoring of the evacuation of civilians from Aleppo. It only asks the secretary-general to provide security and other arrangements “in coordination with the interested parties” - which include the Syrian government now in control of eastern Aleppo - to allow U.N. personnel “to monitor the condition of civilians remaining in Aleppo in light of international humanitarian law.”

Diplomats, speaking on condition of anonymity because consultations are closed, said Security Council members were discussing whether it is possible to merge the two texts.

Earlier on Sunday, Russia’s U.N. Ambassador Vitaly Churkin told reporters as he headed into closed Security Council consultations that he would veto the French-drafted resolution unless it was changed, arguing that allowing monitors to wander in the ruins of eastern Aleppo without proper preparation “has disaster written all over it.

Delattre said that if Russia vetoes the resolution, France will seek an emergency special session of the U.N. General Assembly.

Western powers and Russia have locked horns on Syria, preventing U.N. action, and Russia has vetoed six proposed resolutions on Syria since the fighting intensified in recent weeks.

The U.S. has said that if the Security Council fails to act to protect civilians, it will propose a Security Council resolution - which would not be subject to a Russian veto - calling for an emergency special session of the General Assembly to take action.