In Sudan's Darfur region, African Union officials and human rights observers say the government has begun shelling villages in volatile northern Darfur. The renewed violence follows reports of a government troop buildup in the region, sparking fears violence could escalate.

An official with the African Union peacekeeping force, reached in the the Darfuri capital of El Fasher, said six villages have been attacked. The group Human Rights Watch has also reported bombing of rebel-held villages in north Darfur.

A rebel commander in the Darfur region says several civilians have been killed and thousands more displaced.  
 
Commander Jar El Neby is a member of the National Redemption Front, an alliance of Darfur rebels that did not sign the May 5 Darfur Peace Agreement. He told VOA that he believes the Sudanese government is trying to expand its territory in the region.

"Since three days ago, they are in the area of Um Sidir," he said.  "They have burned the village of Um Sidir, and kidnapped all the villages around Um Sifir area, and killed about five civilians yesterday in Um Sidir area. Until now, I hear the sound of Antonovs in this area. "

El Neby's group and another rebel faction have refused to sign on to the accord, saying it does not grant enough political power to Darfuris, nor enough compensation to victims of the three-year war.

Last week, leading human rights group Amnesty International warned of a potential humanitarian catastrophe in Darfur, charging that Sudan had begun a troop buildup in the region.

Sudan is under intense pressure to allow a United Nations force to take over peacekeeping operations in Darfur.

The African Union force currently monitoring Darfur has struggled with a weak mandate and funding problems.

On Thursday, the U.N. Security Council approved a resolution to send 20,000 U.N. military and police personnel to Darfur.

But, Sudan has said it will not allow the U.N. into Darfur, likening a U.N. force to colonization.

The Darfur conflict began when rebels attacked government positions, complaining that the remote region remained undeveloped due to neglect by the central government.

Sudan is charged with arming militias to crush the rebellion.

Some 200,000 people have died and more than 2 million have been displaced in what the United States calls genocide.