"A place of refuge has now become a battleground in a war that has already taken a horrific toll on civilians," the head of UN World Food Programme (WFP) in Sudan, Eddie Rowe, said in a statement on Wednesday.

"This has forced WFP to put on hold food deliveries in some locations in Gezira state at a time when people need our help the most."

An estimated 300,000 have fled fighting in the state since Friday last week, the agency said.

WFP had been providing food aid to 800,000 people in Gezira and to those displaced by the conflict in Sudan's capital Khartoum.

There are concerns that the spill-over of the fighting into Gezira could escalate Sudan's humanitarian crisis.