The UN Security Council will on Wednesday hold urgent talks on the failure of a 30-day ceasefire to take hold in Syria, diplomats said.
France and Britain requested the meeting that will be held behind closed doors at 1500 GMT, as air strikes and clashes continue in the Syrian enclave of Eastern Ghouta.
Backed by Russia, the council unanimously adopted on February 24 a resolution demanding the 30-day cessation of hostilities to allow deliveries of humanitarian aid and evacuations of the sick and wounded.
A first aid convoy reached Eastern Ghouta on Monday but the operation was cut short as air strikes pounded the enclave, killing at least 68 civilians, according to a human rights monitor.
Air strikes and artillery and rocket fire on the last major rebel-held enclave near the capital Damascus have killed hundreds and devastated residential areas since they began on February 18.
The Syrian Observatory for Human Rights said 800 civilians -- including at least 177 children -- have been killed since Russia-backed Syrian forces launched an assault on the besieged enclave outside Damascus on February 18.