Syrian regime and allied forces pushed deeper into eastern Ghouta on Monday and have now retaken a third of the opposition-held enclave, a monitor said.
"Regime forces now control 33 percent, or a third, of besieged eastern Ghouta," the Syrian Observatory for Human Rights, a Britain-based monitor, said.
Syria's Central Military Media, which claimed the regime had secured 36 percent of the enclave, says troops are continuing their advance from the east and are only 3 kilometers, or 1.8 miles, from meeting troops advancing from the west, which would achieve the partitioning of eastern Ghouta into two parts.
A 46-truck international aid convoy of the United Nations and key aid agencies crossed a final Syrian army checkpoint Monday and began to enter eastern Ghouta.
Ali al-Za'tari, a senior United Nations official with the convoy, told Reuters it would take "many hours" to offload the aid in the enclave and that it might be "well after nightfall" before it could leave eastern Ghouta.
"Feels like racing with time," Pawel Krzysiek of the International Committee of the Red Cross said in a tweet.
The delivery will be the first to the region in nearly three weeks.
The U.N.'s office for humanitarian affairs and the World Food Program says Monday's convoy to the town of Douma in eastern Ghouta will consist of 46 truckloads of health and nutrition supplies, along with food for 27,500 people in need. U.N. officials had said lack of approvals and consensus among the warring parties, as well as the limited duration of a daily, five-hour Russian-ordered humanitarian pause, had made aid delivery impossible.
Fresh air raids by the Assad regime on the besieged opposition-held enclave of eastern Ghouta killed at least 14 civilians overnight, the Syrian Observatory for Human Rights said earlier Monday.
Barrel bombs -- crude, improvised munitions that cause indiscriminate damage -- were used, including on the town of Hammuriyeh, where 10 people were killed, it said.
The Russian military said Monday that Syrian opposition groups had promised to let civilians leave their eastern Ghouta enclave near Damascus in exchange for humanitarian aid, Interfax news agency reported.
Earlier, Russia introduced a daily ceasefire in the severely bombed area but the military said that Syrian opposition had prevented local residents from leaving.
A total of 400,000 people in the region have largely been cut off from humanitarian aid, and activists have warned that the situation is dire, with food and medical supplies quickly running out. More than 600 civilians have been killed in the last two weeks alone.