SUDAN: Sudanese troops yesterday surrounded two refugee camps in Darfur preventing relief workers delivering aid, according to United Nations officials, writes Rob Crilly, in Nairobi
The Sudan government blamed Arab tribesmen who had gathered in the area after being attacked by rebels.
Ms Christiane Berthiaume, spokeswoman for the World Food Programme, said at least 160,000 people in western Darfur could not be reached by road.
She said the UN food agency had relocated 88 aid workers.
"Agencies have been denied access to these camps since this morning," Ms Berthiaume said. More than 1.5 million people have been driven from their homes by violence in Darfur.
Arab nomads are locked in a war with rebels from the region's black African population over scarce resources, including water and food.
The UN estimates that 70,000 people have died from disease and malnutrition in the past seven months. Human rights groups have accused the Arab Janjaweed militias of genocide and of using rape as a weapon.
Mr Ibrahim Hamid, Sudan's humanitarian affairs minister, denied there was a siege. "What happened is that angry Arab tribesmen gathered after the abduction of 18 of their men by the rebels. But the African Union has been alerted and they said they would bring those abducted out of the mountainous areas of Zaleinge."
Aid agencies say security in the region has decreased in recent weeks despite a ceasefire, monitored by AU troops, and the threat of UN sanctions.
The UN Security Council is to meet in Nairobi later this month to discuss ending the conflict.
AU mediators have drafted a fresh security agreement during peace talks in Abuja, the Nigerian capital. It includes making the region a no-fly zone.
Rebels have repeatedly accused the Khartoum government of giving air support to the Janjaweed fighters.