BBC
The Syrian government bombarded the besieged Damascus suburb of Darayya hours after the arrival of its first food aid since 2012, residents said.
Darayya's city council said 28 barrel bombs were dropped from helicopters, preventing the aid from being delivered to residents.
Overnight, trucks carrying medicine, food and flour reached the town.
A member of the Darayya City Council said there had been "intense random barrel bombing" of the area over three hours until midday, hindering the distribution of the aid delivered overnight by the UN and Syrian Red Crescent convoy.
Rebel-held Darayya, which is surrounded by government forces, was among the first to report protests against President Bashar al-Assad's government.
Earlier, the UN said its aid delivery had provided food rations including rice, lentils, sugar and oil for 2,400 people as well as wheat flour for all the estimated 4,000 people in the town.
The convoy also contained 1.9 tonnes of medicines, antibiotics and vitamins, the World Health Organisation (WHO) said.
However, burns kits to treat about 30 people with dressings and painkillers could not be delivered as they were rejected by the government, the WHO said.
The supplies are thought to be enough to last the besieged population a month.
"We are hoping that this will lead to a much more sustained, durable access to Darayya and other besieged areas in Syria," said Jens Laerke, a UN spokesman.
He said there were about 4.6 million Syrians living in besieged and hard-to-reach areas who were in need of supplies.
On Thursday the UN's special envoy for Syria, Staffan de Mistura, said the Syrian government had given permission for aid to be delivered to 19 areas designated as "besieged" in the country, where an estimated 600,000 people live.
The US, UK and France have called for air drops of aid and Mr de Mistura said he believed this pressure had led the Syrian government to allow aid to enter besieged rebel-held areas.