A strike on a humanitarian aid convoy in Aleppo, Syria, has hit 18 of the 31 trucks taking part in the mission, a UN spokesman said.
Dozens of airstrikes hit rebel held parts of Aleppo after the truce ended, leaving at least 36 people dead, including 12 in the aid convoy, according to activists and a monitoring group. Among the dead were aid workers, the reports said. Dozens were injured.
The UN spokesman said the source and type of attack is under investigation.
The strike on the convoy occurred after dark on Monday just hours following an announcement by the Syrian army that a week-long ceasefire was over. A warehouse was also hit in the attack on the aid convoy, the UN official said.
Rebels and the government blamed each other for the collapse of the deal, brokered by the US and Russia.