The United States called on the Sudanese authorities Friday to clamp down on pro-government militiamen who are accused of atrocities against civilians in the western region of Darfur. Sudanese forces and Arab militia allies have been trying to put down a rebellion in Darfur for the past year.

The U.S. statement, which coincided with a U.N. Security Council briefing on Darfur, expressed grave concern about the deteriorating situation in Darfur - where the State Department said government-supported militiamen known as the "Jingaweit" are continuing to burn villages and abuse civilians and creating a massive humanitarian crisis.

State Department spokesman Adam Ereli told reporters the unrest has driven as many as 700,000 people from their homes inside Sudan and forced an estimated 110,000 others to seek refuge in neighboring countries, mainly in Chad.

He said both the lives and livelihoods of those affected are at imminent risk and made clear the United States looks to the Khartoum government to rein-in the militiamen.

"We condemn the atrocities going on in Darfur in the strongest terms, and we call on the government of Sudan to take immediate steps to stop the 'Jingaweit' and to allow outside monitoring of the situation there," he said. "I would also note that talks have begun in Chad between the government of Sudan and the opposition groups in the presence of officials from the United States and the European Union. We welcome the start of those talks and we urge both the government of Sudan and the opposition groups to cooperate in negotiating an immediate humanitarian cease-fire that will facilitate unrestricted humanitarian access."

Accurate casualty figures are hard to come by. But several thousand people are believed to have been killed in the Darfur fighting, which erupted last February when two African rebel groups launched a revolt - accusing the Islamic government in Khartoum of neglecting the poor region and arming the Arab militias to attack local villages.

A United Nations official recently likened the Darfur fighting to the 1994 Rwandan genocide and said the fighting had created one of the world's worst humanitarian situations.

The United States has come under criticism on the tenth anniversary of the Rwandan crisis for not doing enough to halt that bloodshed.

Defending U.S. handling of Darfur, spokesman Ereli said the United States has been very active in calling world attention to the problem and providing humanitarian aid, while working assiduously on the diplomatic front to bring about peace talks and pressure the Khartoum government to control the militias.

The Darfur conflict is distinct from Sudan's 20-year-old north-south civil war, which is close to being settled in Kenyan-mediated peace talks.

Mr. Ereli said he did not think that a final deal in Kenya between the Khartoum government and southern rebels depends on peace in Darfur, but said it is clear that important compromises need to be made in both places.