Secretary of State Colin L. Powell will travel to Sudan's strife-torn Darfur region next week to press Khartoum to disarm pro-government Arab militias that have displaced more than a million black Africans through attacks that have left thousands dead.

The announcement of Powell's unexpected trip came as U.S. officials disclosed that the Bush administration was drafting a U.N. Security Council resolution that would sharply criticize Sudan for failing to halt the violence and demand that it grant broader access for humanitarian relief workers. Senior U.S. officials met in Washington yesterday to flesh out details of the new resolution, which could coincide with Powell's visit.

U.S. officials said they are considering a range of measures, including an arms embargo and a freeze on the financial assets of individuals linked to the atrocities. But they say they have not decided whether to impose the sanctions on Sudanese government officials or just on commanders of the Janjaweed militia responsible for most of the violence.

Administration officials said that while they believe Sudan continues to hinder the efforts of aid workers seeking to provide relief in Darfur, they are confident that Sudan will bow to international pressure to respond to the humanitarian crises.

"The Sudanese government does respond to unified international pressure," said Andrew S. Natsios, head of the U.S. Agency for International Development. "We want to put more public pressure on the Sudanese government to restrain the Janjaweed."

Powell's visit next Tuesday and Wednesday -- which was approved by President Bush -- is also designed to increase the pressure. Powell would be the highest level U.S. official to visit the Sudan since President Jimmy Carter's secretary of state, Cyrus R. Vance, met briefly with Sudanese officials during a refueling stop in 1978.

Powell's trip "is intended to continue to call attention to the dire humanitarian situation in Darfur, to do whatever we can to stop the violence there and to make sure that the needy people of that region are receiving whatever supplies we can get to them," State Department spokesman Richard A. Boucher said.

Boucher added that Powell will place the onus on the Sudanese government. "We believe that much of the hardship is being caused by the violence perpetrated by the militias, that we know the militias are being supported by the government and that the government needs to bring those militias under control," he said.

U.S. officials are also actively considering whether to declare that genocide is taking place in Darfur. Pierre-Richard Prosper, the U.S. war-crimes ambassador, told lawmakers on Capitol Hill yesterday that "we see indicators of genocide, and there is evidence that points in that direction."

At least 10,000 people have been killed and as many as a million displaced in Darfur since black African rebels rose up in February 2003, accusing Khartoum of discrimination and neglect. The government's response was to give the militias free rein, and they have been accused of conducting a scorched-earth campaign against the rebel Justice and Equality Movement and the Sudan Liberation Army.

Natsios yesterday presented U.N. Secretary General Kofi Annan and representatives of the five permanent members of the Security Council on Wednesday with aerial photographs of hundreds of villages that have been burned to the ground.

Natsios said the State Department and USAID purchased commercial satellite photos showing 576 villages, including 300 that have "been completely destroyed" and 76 that have been "severely damaged. The rest are fine, and they are all Arab. It's clear that ethnic cleansing is going on here," Natsios said.

Annan, who so far has been reluctant to describe the forced displacement of black African civilians in Darfur as genocide or ethnic cleansing, will fly to Khartoum on Wednesday before visiting a camp for displaced civilians in Darfur. He will then travel to Chad to talked to Sudanese refugees and return to Khartoum on July 2.

U.S. officials said they face a battle to persuade Sudan's strongest supporters on the council, China and Pakistan, to back the resolution.

Algeria, the council's sole Arab country, indicated it was willing to consider a new U.S. resolution. "The international community is getting impatient, and they have to act quickly and efficiently," said Algeria's U.N. ambassador Abdallah Baali.

Lynch reported from the United Nations.