Several aid agencies working in West Darfur have suspended work in Um Dhukun, affecting about 100,000 people, including refugees from Chad and Central African Republic (CAR), a spokesperson said.

Citing continuing violence, the charities Oxfam GB, Save the Children-Spain, Mercy Corps and Triangle said they had temporarily suspended all but essential work after increases in violent attacks on aid workers in the area.

"We have temporarily withdrawn; we need local authorities and the people of Um Dukhun to give us assurances that this will be secure when we return," Caroline Nursery, country director for Oxfam in Sudan, said.

Um Dukhun is at the southernmost end of West Darfur and close to the borders with Chad and the CAR. According to the agencies, their decision was informed by several incidents in the past three weeks. Among others, a humanitarian convoy was shot at and robbed outside the town, an aid agency security was guard beaten into a critical condition, and a vehicle belonging to Oxfam was hijacked in a camp sheltering refugees and displaced people.

"Incidents such as these are now an all-too-frequent occurrence in Darfur and humanitarian vehicles are being hijacked every few days," said Nursery. "This is seriously threatening our ability to respond to the enormous humanitarian need in the region."
Several attacks on humanitarian targets forced a significant withdrawal of aid workers in December. An attack in Gereida, South Darfur, brought the number moved to 400. Oxfam and Action Contre le Faim stopped operations after they lost 12 vehicles. The United Nations Humanitarian Coordinator in Sudan, Manuel Aranda da Silva, described the attacks at the time as "crippling".

"It is very difficult to be sure who the attackers are," explained Nursery on Monday. "There is increasing factionalisation so the rebel groups and the Arab militias are all splitting into smaller groups and nobody knows who is in control in different areas."

At least 200,000 people are estimated to have died since the Darfur conflict began in 2003 between government forces, allied Arab militias and rebels seeking greater autonomy. More than two million people have been displaced inside Sudan and in neighbouring Chad and 12 humanitarian workers killed since May 2006.

"We greatly regret any suspension, even temporarily, of assistance to people in need, but such attacks on humanitarian workers are not acceptable and cannot be tolerated," Oxfam and Save the Children said in a joint statement. "All parties to the conflict in Darfur must respect humanitarian operations and do more to bring those responsible to account."