Syrian and Russian forces kept up military pressure on rebel-held Eastern Ghouta on Thursday as their controversial unilateral truce failed to yield a humanitarian breakthrough.
More than 40 trucks loaded with aid were unable to reach the 400,000 people living in the battered enclave, prompting fresh calls for a UN ceasefire to be implemented.
A five-hour daily "pause" announced by Moscow on Monday has led to a reduction in the bombardment that killed hundreds in only a few days and sparked global outrage last month.
But the humanitarian corridor offered by Russia for civilians to flee remained ostensibly empty for a third day running, with distrust running high on both sides.
The only civilians to leave Eastern Ghouta this week were a septuagenarian Pakistani man who moved to Syria 44 years ago and his wife, according to the local Red Crescent.
Syrian aircraft carried out strikes Thursday before the 9:00 am local time start of the "truce," killing seven civilians, according to the Syrian Observatory for Human Rights, a Britain-based war monitor.
Ground battles were also taking place in Al-Shaifuniyah which lies in the enclave's northeastern region and has been extensively destroyed in recent days.
A spokesman for the Syrian Civil Defence volunteer rescuers, known as the "White Helmets", said access to the area had been very difficult.
"There is hardly any life there. It is completely destroyed and there are people under the rubble," Siraj Mahmud told AFP.
Air strikes have eased compared with last week when the joint Syrian and Russian aerial campaign against Eastern Ghouta killed up to 100 civilians a day.
But the death toll for the assault launched on February 18 continued to mount even after Russia's "humanitarian pause" kicked in, as rescuers found bodies they had been unable to access.
In the town of Hazeh, rescuers working with rudimentary equipment were painstakingly hoisting buckets of gravel from a basement where they feared up to 21 were buried alive by a strike on February 20.
They have only retrieved six bodies so far.
"I left my daughter in the basement with her husband and his family," said 60-year-old Abu Mohamed.
"I came back the next morning. I found the building collapsed and until now I haven't found my daughter nor her husband's family," he said.
According to the United Nations, three quarters of all private housing in Eastern Ghouta have been damaged and hundreds of civilian need life-saving medical evacuations.
The Russian daily "pause" falls far short of a 30-day ceasefire voted for by the United Nations Security Council on Saturday and yet to be implemented.
UN agencies and aid organisations have argued that the five-hour window was too short for aid deliveries.
"When will your resolution be implemented?" top UN relief official Mark Lowcock asked Wednesday, staring fixedly at Security Council members who listened in complete silence.
Russia and its allies in Syrian President Bashar al-Assad's regime have blamed the humanitarian deadlock on the armed groups controlling Eastern Ghouta.