The government of Sudan announced Saturday that it would send troops to the western region of Darfur and disarm Arab militias known as the Janjaweed to end violence that has displaced more than 1 million villagers.

In a statement issued jointly with the United Nations, the government said it was committed to start immediately disarming the Arab militias, which are accused of killings, rapes and beatings that have driven the villagers, who view themselves as African, from their homes. Aid groups and witnesses said the government armed the militias and bombed villages, charges officials have denied.

The communique was signed at the airport in Khartoum moments before U.N. Secretary General Kofi Annan departed the country after a two-day tour of refugee camps in Darfur and neighboring Chad, where more than 150,000 refugees live in tent cities.

Sudanese officials promised to deploy a "strong, credible" police force to protect the camps and other areas vulnerable to attacks, the communique said. Officials also promised to develop a system that would allow women who have been raped during the crisis to bring charges against alleged assailants. Sexual violence against women in Darfur emerged as a major concern during Annan's visit, his aides said.

On Friday, Annan visited the crowded Iridimi camp in Chad, a maze of stick and straw shelters housing 15,000 Sudanese refugees, 44 miles west of the border with Sudan. Refugees at the sand-blown camp formed a giant circle as they awaited his arrival.

On Friday night, after meeting with Sudan's president, Lt. Gen. Omar Hassan Bashir, Annan told reporters: "The Janjaweed must be stopped, and a cease-fire must be respected by all."

Secretary of State Colin L. Powell also visited Sudan this week, pressing the government to disarm the Janjaweed. The United States began circulating a U.N. Security Council resolution Wednesday that would impose an arms embargo and travel ban on the militias.

The Darfur conflict began in early 2003, when the Justice and Equality Movement and the Sudan Liberation Army, two African rebel groups, attacked military installations, charging that the government had treated Africans unjustly in their struggles with Arab herders over land and resources. In response, the government began arming the militias and bombed African villages, according to human rights groups and U.N. reports. An estimated 30,000 have been killed in the conflict.

Human Rights Watch and aid groups expressed skepticism Saturday about the government's promise to disarm the militias, citing reports that several villages in southern Darfur were bombed on Thursday.

U.N. emergency relief coordinator Jan Egeland warned that the Janjaweed must not be incorporated into the Sudanese army or used to guard citizens that they had earlier attacked, a development aid workers fear is already happening. Some of the militia fighters were now wearing government uniforms, aid workers said.

"You don't want a case where the wolf is guarding the sheep," Egeland said. "We will have to monitor this closely."