An international aid convoy has been hit by an air strike near the Syrian city of Aleppo according to the Syrian Red Crescent.
At least 18 of the 31 vehicles were struck as they were delivering assistance for 78,000 people in a rebel-held area.
One report said at least 12 people were killed, most of them drivers.
UN Special Envoy for Syria, Staffan de Mistura, said it was an “outrage”.
“The convoy was the outcome of a long process of permission and preparations to assist isolated civilians,” he said in a statement.
Aid deliveries to besieged areas were a key part of the cessation of hostilities deal brokered by the US and Russia seven days ago.
However earlier the Syrian military announced in a statement that the effect of that “truce regime” which came into force on September 12 was now at an end.
Airstrikes began almost immediately on Aleppo and other major cities.The Syrian military and rebels had accused each other of violating the truce.
The Syrian Observatory of Human Rights claims the aid convoy was hit by Syrian or Russian warplanes.