The World Food programme has said that it has suspended aid drops to the besieged Syrian city of Deir Ezzor because of heavy fighting after a fierce assault by the Islamic State group.

IS has besieged Deir Ezzor’s 100,000 residents since 2015 and already controls large parts of the city, but advanced further inside remaining government-held territory.

The WFP has been dropping humanitarian aid into Deir Ezzor since April 2016, and the government-held area is the only place in Syria where the agency has permission for the drops.

The I.S assault has managed to divide the east of the remaining government-held parts of the city from the west.

It has also cut the route running from the city’s key military airport, limiting the government’s ability to bring in supplies and military reinforcements.

The Britain-based Syrian observatory for human rights monitor said that Syria’s military and allied Russian forces were carrying out air strikes against is, as government troops battled the militants on the ground.

The monitor said that three days of fighting had killed at least 116 people, among them 21 civilians, 37 members of regime forces and 58 IS fighters.