BEIRUT — A unilateral five-hour cease-fire decreed by Russia to pause the violence around a besieged suburb east of Damascus failed on Tuesday to stop the fighting, permit the delivery of aid or encourage any civilians to escape.

Moscow said it was committed to continue the observance of a daily truce between 9 a.m. and 2 p.m. to allow aid to enter and civilians to leave the besieged Eastern Ghouta area.

But aid agencies said the five-hour pause was too short to organize the delivery of food and medicine for 350,000 people across a front line in a war zone. Civilians said they were too afraid of the ongoing bombardments and of what may await them behind government lines once they escaped the area.

Though the bombardments lessened during the hours of the truce, mortars landed near a humanitarian corridor opened by the Syrian government on the eastern edge of the enclave, and there was scattered mortar fire elsewhere as well. Rebels and the Syrian government traded accusations for the violations, with the official Syrian Arab News Agency saying “terrorists” had targeted the crossing to prevent civilians from fleeing.

The five-hour daily “humanitarian pause” called for by Russia appeared intended to meet halfway the demand of Saturday’s United Nations Security Resolution for an immediate halt to all fighting across Syria, including Eastern Ghouta, which has been the focus of a renewed government offensive for the past 10 days.

Hundreds of people have been killed, most of them civilians, since a surge of intensified airstrikes began Feb. 19, as the government renewed a push to subdue the last major rebel stronghold near the capital. The scenes of bloodshed and civilian suffering, relayed in photographs and videos by activists inside the besieged enclave, spurred the effort at the United Nations to secure a 30-day truce.

The rebels have struck back, firing volleys of mortars into Damascus and killing at least 36 people in the capital, according to the pro-government al-Watan daily. Mortars fired on Tuesday injured 17 people in the Damascus area, SANA reported.