GENEVA (Reuters) - The U.N.’s World Food Programme has temporarily suspended air drops of vital supplies to the eastern Syrian city of Deir al-Zor due to heavy fighting there, a spokeswoman said on Tuesday.

The WFP, whose last drop there was on Sunday, has carried out 177 air drops for 110,000 people in the city since beginning the operation in April, spokeswoman Bettina Luescher said. “We put it on hold on Sunday,” she told a Geneva news briefing.

Islamic State has launched its fiercest assault in a year against a besieged Syrian government enclave in the city of Deir al-Zor, trying to cut it off from a nearby military air base in a battle that has killed dozens.