Air strikes killed 37 people in a Syrian town hours before a ceasefire began, rescuers have said.
The rebel group Faylaq al-Rahman, one of at least three operating in the sprawling region, said intense government attacks targeted the area it controls on Thursday.
Rescuers, known as White Helmets, said the casualties were from an air strike that hit an underground shelter in the town of Arbeen in the eastern Ghouta region near the capital, Damascus.
Rebel spokesman Wael Oweilan said on Friday negotiations that with Russia will follow to allow for the evacuation of civilians from the area.
A similar deal with another rebel group, Ahrar al-Sham, led to the evacuation of hundreds of fighters and civilians from Harasta, another eastern Ghouta town.