The United Nations has expressed concern about the expulsion of its top humanitarian official from South Darfur, Sudan. As Derek Kilner reports from VOA's East Africa Bureau in Nairobi, the move is the latest confrontation between the Sudanese government and international humanitarian groups in the region.

The South Darfur government has expelled Wael al-Haj-Ibrahim, the top official of the U.N. Office for the Coordination of Humanitarian Affairs in the state capital, Nyala. The office is responsible for coordinating international aid efforts in the state.

According to the United Nations, Ibrahim, a Canadian national, has been barred only from South Darfur and can stay in Sudan.

U.N. spokeswoman Orla Clinton tells VOA the organization has not yet received a clear explanation of the government's actions.

"He was forced to leave South Darfur. This is a directive from the state government. Today, we are having meetings with the government here in Khartoum on this," said Clinton. "The only indication we have been given was that he was not complying with the humanitarian acts. Now, we don't exactly know what that means and we are looking for clarifications on this. So, we are hoping to have those clarifications today."

Clinton says poor treatment of humanitarian workers in Nyala, which hosts the largest concentration of displaced people in the region, has been a recurring problem.

"This is not so much about one person. It is about a broader issue relating to humanitarian staff. Of course, we are very concerned about the potential implications of this, particularly in a place like Nyala, where we have up to one million IDPs [internally displaced people] in need of assistance in the camps. It is not the first time that somebody has been removed from Nyala, so we would like to see that our humanitarian workers are protected," added Clinton.

In late October, the world body and international human rights groups accused Sudanese police of forcibly moving displaced people from camps near Nyala. The government has advocated for closing the camps, saying they are too dirty and insecure, but has denied forcing anyone to move.

A joint U.N.-African Union peacekeeping force is scheduled to deploy in Darfur by January. Peace negotiations between the Sudanese government and rebels in Libya are on hold, while international mediators attempt to convince several key rebels to attend the talks.

U.N. estimates are that 200,000 people have been killed and more than 2.2 million others have been displaced by fighting in Darfur since 2003.