BEIRUT (Reuters) - Syria’s army general command said warplanes from the U.S.-led coalition bombed a Syrian army position at Jebel Tharda near Deir al-Zor airport on Saturday, paving the way for Islamic State fighters to overun it.

The air strike killed Syrian soldiers and was “conclusive evidence” that the U.S. and its allies support the jihadist group, the Syrian army said in a statement, noting that the strike was “dangerous and blatant aggression”.

The U.S.-led coalition has been conducting air strikes against Islamic State since September 2014. In December Damascus accused the coalition of striking an army camp near Deir al-Zor, but Washington said it was done by Russian jets.

A strike list issued by the U.S. on Saturday said it had carried out a strike at Deir al-Zor against five Islamic State supply routes, as well as strikes near Raqqa and elsewhere in Syria.

Syria’s army controls Deir al-Zor airport and parts of the city which are otherwise entirely surrounded by territory held by Islamic State.

The United States and Russia agreed a deal on Syria last week, involving a ceasefire which came into effect on Monday, aid deliveries to besieged areas and eventual joint targeting of militant jihadist groups if the truce works out.

Syria’s five-year civil war between President Bashar al-Assad and rebels seeking to topple him has drawn in regional and global powers and allowed militant jihadist groups including Islamic State to gain territory and inspire attacks.