A fresh outbreak of fighting between Angolan government forces and Unita rebels could lead to food shortages in the city of Kuito, warned the United Nations food agency.

Reports say Unita forces have been shelling around the central city for a second day.

When Angola's civil war resumed last December, it began around Kuito, creating a humanitarian disaster as refugees from surrounding areas flooded into the city.

Unita forces have put Kuito under siege once again and there are renewed fears for the civilian population.

The World Food Programme had been flying aid into the city because it is not safe to reach it by road.

But Kuito's airport is now closed and the agency says it has stocks to last two weeks at most.

The last airlift of food took place on Monday and the WFP is not sure when it will be able to reach the city again.

The UN says food stocks in Cuito are only good for two weeks

It has now taken the decision to cut back distributions to many of the 70,000 people it has been feeding in Kuito so that it can concentrate on the most vulnerable of them - pregnant women and children.

Most foreign aid workers left Kuito earlier this week, as Unita rebel forces closed in on the city, with terrified civilians fleeing ahead of them.

Details are sketchy, but fighting is reported to be continuing around Kuito, as well around the town of Malanje, hundreds of kilometres further north.