A Red Cross aid convoy was denied access to a besieged Syrian town that has not received outside supplies for three years.
Daraya, a town on the outskirts of Damascus, has been held by rebels and subsequently besieged by government forces since November 2012. This delivery would have been the first since then.
"Sadly our aid convoy was reufsed entry to Daraya, despite being given prior clearnace from all sides," the International Committee of the Red Cross said on Twitter.
The five-truck convoy had planned to deliver baby milk, medical and school supplies.
The United Nations said this month that Syria's government was refusing UN demands to deliver aid to hundreds of thousands of people.
"Despite having obtained prior clearance by all parties that it could proceed," the convoy was not allowed through, a statement from the International Committee of the Red Cross (ICRC) and UN said.
"Daraya has been the site of relentless fighting ... and we know the situation there is desperate", said Yacoub El Hillo, UN Humanitarian Coordinator in Syria.
"Civilians trapped here are in need of humanitarian aid. We were hoping that today's delivery of life-saving assistance would have been a first step and lead to more aid being allowed in."
The ICRC's Syria head, Marianne Gasser, said it was "tragic that even the basics we were bringing today are being delayed". The supplies included medical aid, nutrition items for children and hygiene kits.
"We urge the responsible authorities to grant us access to Daraya, so we can return with desperately needed food and medicines," they said, according to AFP.
Government forces shelled parts of Daraya on Thursday, killing a civilian, according to the Syrian Observatory for Human Rights.
It is estimated that 4,000 civilians are trapped in the city, according to Senior UN official Jan Egeland, who spoke to reporters on Thursday in Geneva.
Meanwhile, a truce in Aleppo expired on Wednesday night.
The truce was made after a spike in violence that killed over 300 civilians last month.
There have been no deaths in the eastern rebel-held areas in the city since the truce ended, however two civilians were killed in sniper fire in the regime-controlled west, according to the Syrian Observatory of Human Rights.
Additional Reporting by Reuters
