The UN Security Council on Wednesday met behind closed doors to step up pressure on Russia and Syria to abide by a ceasefire and allow deliveries of humanitarian aid and evacuations from Eastern Ghouta.
France and Britain requested the urgent meeting as the Syrian government sent militias as reinforcements to the rebel enclave and heavy airstrikes battered key towns.
Dutch Ambassador Karel van Oosterom, who holds the council presidency, told reporters after the three-hour meeting that council members "expressed concern about the humanitarian situation" and "reiterated its call for implementation" of the ceasefire resolution.
The council heard a briefing via videoconference from UN peace envoy Staffan de Mistura who offered to help broker a deal with Russia to allow fighters in Eastern Ghouta to leave, according to a diplomat.
The council diplomat who attended the meeting said there was strong support for the envoy's offer to help negotiate the departure of the fighters in a bid to halt the violence.
Three armed groups fighting President Bashar al-Assad's forces have written to the Security Council offering to dissassociate themselves from jihadists and help organize their expulsion from Eastern Ghouta.
Council members also discussed plans for a new aid convoy to travel to the main town of Douma in Eastern Ghouta on Thursday to complete the delivery of aid that was cut short during shelling on Monday.
Nearly half of the food carried on the 46-truck convoy which had been approved by the Syrian government could not be delivered and part of the medical and health supplies were removed from trucks by Syrian authorities, the UN said.
UN Secretary-General Antonio Guterres on Tuesday called for the aid convoy to have safe access to Eastern Ghouta.
Swedish Ambassador Olof Skoog, who negotiated the ceasefire resolution along with Kuwait, said ahead of the meeting that implementation of the truce remains "totally and completely inadequate."
"So far we see minimal signs only from the Syrian authorities to implement the resolution and we are very, very disappointed about that," Skoog told reporters.
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.
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.