Western powers lashed out at Syria's government, accusing regime forces of dropping barrel bombs on the town of Daraya hours after it received its first food aid in almost four years. The strikes, using crude unguided explosive devices, came as Arab-Kurdish fighters said they had encircled a stronghold of Islamic State (IS) fighters in northern Syria, cutting off a major supply route. French Foreign Minister Jean-Marc Ayrault accused Damascus of "extraordinary duplicity" over the bombings, which came just as aid workers were beginning to distribute supplies to thousands of desperate people. Ayrault said he was "outraged beyond words", declaring the end of an already shaky ceasefire and calling world powers to meet.A convoy of trucks carrying food arrived in Daraya late Thursday, delivering rice, lentils, sugar, oil and wheat flour to civilians for the first time since the regime laid siege to the town in late 2012.
Assad's forces bombarded the town shortly after, according to a witness and human rights monitors, dropping indiscriminate barrel bombs from helicopters as residents shared food.
Local council member Shadi Matar said aid had not yet been distributed "because of the intensity of the raids".
US State Department spokesman Mark Toner said "such attacks are unacceptable in any circumstance, but in this case they also hampered the delivery and distribution of badly needed assistance".
Nearly 600,000 people live in besieged areas in Syria, most surrounded by government forces, and another four million in hard-to-reach areas, according to the United Nations.UN-backed peace talks on ending the war stalled in April when the opposition walked out over lack of humanitarian access.
Aid agencies said supplies reached Douma on Friday -- the first UN delivery since autumn 2013, according to the Syrian Observatory for Human Rights, a Britain-based monitoring group.
The Syrian Arab Red Crescent said 39 trucks took food and non-food items including medicines into the besieged town.
But the UN's humanitarian agency was still awaiting Damascus's approval to deliver aid to two more of Syria's besieged areas: Al-Waer in Homs province and Zabadani in rural Damascus.
- 'No way out' -Elsewhere, Arab-Kurdish fighters backed by the United States on Friday cut IS's main supply route between Syria and Turkey, in a major setback for the jihadists.
IS lost control of a vital supply artery when the troops completely surrounded the town of Manbij, at the heart of the last stretch of territory along Turkey's border still under the jihadists' control.
IS has come under growing pressure on various fronts in Syria and Iraq, where it established its self-declared "caliphate" in 2014.
"The Syrian Democratic Forces (SDF) cut off the last road from Manbij to the Turkish border," said the Observatory.
The US envoy to the anti-IS coalition backing the SDF, Brett McGurk, said the move had severed an important route for IS fighters looking to attack Europe.
"ISIL terrorists now completely surrounded with no way out," he wrote on Twitter, using another name for IS."Manbij is where we believe the Paris attackers, the Brussels attackers, they all kind of pulsed through this area," McGurk said. "From Raqa up to Manbij and then out to the capitals where they had organised their attack."
About 20,000 people are still living in the town, which had a pre-war population of about 120,000 -- mostly Arabs, but about a quarter Syrian Kurds.
This week the SDF, backed by coalition air strikes, cut the road north out of Manbij to the IS-held border town of Jarabulus, which the jihadists had used as a transit point for fighters, money and weapons.
The SDF also blocked the road south out of Manbij heading to IS's de facto capital of Raqa."For the jihadists to reach the Turkish border from Raqa, they now have to take a route that is more dangerous because of regime troops nearby and Russian air strikes," Abdel Rahman said.
Moscow and Washington -- despite backing different sides in Syria's five-year conflict -- have both focused efforts on fighting the jihadist group.
Syria's war has killed more than 280,000 people and displaced millions since it started in 2011 with the brutal repression of anti-government protests.