Air strikes hit aid trucks outside a Syrian Arab Red Crescent centre in northern Aleppo province on Monday, a monitor said, hours after the army declared a truce over.

The Britain-based Syrian Observatory for Human Rights did not immediately report any casualties in the raids on the Orum al-Kubra area.

The strikes came shortly after Syria's army declared an end to a week-long ceasefire between the regime and non-jihadist rebels agreed between Russia and the United States.