Aid agencies say at least 500,000 Syrians living under siege have not had enough food in weeks - and some of them are starving. Aid deliveries in coming days are expected to alleviate the suffering.
A UN airplane dropped desperately needed food and medical supplies on Wednesday for the people who have been unable to flee from the Syrian city of Deir el-Zour.
Arab Red Crescent teams on the ground confirmed the pallets landed on target.
Stephen O'Brien, head the UN's World Food Program (WFP), reported the news to the UN Security Council on Wednesday.
"Earlier this morning, a WFP plane dropped the first cargo of 21 tons of items into Deir el-Zour," O'Brien told the Council.
Deir el-Zour, which lies along the banks of the Euphrates River in eastern Syria and had a pre-war population of about 240,000, has been besieged by "Islamic State" (IS) fighters for weeks, making safe aid deliveries by ground impossible.
The city's last aid delivery came in January, when Russia airdropped aid as part of its campaign to support Syrian President Bashar al-Assad.
Ceasefire Friday midnight
With a ceasefire set to take hold at midnight on Friday, aid agencies are gearing up to deliver tons of food and medical supplies to cities and towns that have been under siege by various warring parties, including IS militants, Syrian military forces and opposition groups.
Aid agencies report that hundreds of thousands of Syrians are desperate for food, with some on the verge of starvation, and also in need of medical supplies.
So far the UN and its partners have delivered aid to 110,000 residents in besieged areas. The UN is still waiting for approval to reach 170,000 more people under siege but, O'Brien said "we expect those approvals to happen immediately."
The UN has called on all sides to lift starvation sieges of all Syrian cities. The UN estimated that nearly 500,000 people live under siege conditions, although some NGOs have said the figure is much higher.
The Russian military said it is negotiating the cessation of hostilities in some areas as part of efforts to implement the ceasefire deal brokered by the United States and Russia.
Konashenkov said ceasefire declarations already have been signed by the government and opposition representatives in several areas in the provinces of Homs and Latakia.
The ceasefire agreed to by Washington and Moscow calls on Russia to halt its air campaign against groups that respect the truce. The ceasefire, however, excludes several groups, including the Islamic State, the al-Nusra Front, an al-Qaeda affiliate branch in Syria, and other militant groups.
bik/sms (AP, AFP, dpa)