Sudan's president promised to send troops to stop militia violence that has forced 1 million people from their homes in the state of Darfur (search), a Sudanese official said Friday after meeting with U.N. Secretary-General Kofi Annan (search).

The pledge came as the United States raised the possibility of sanctions against Sudan if the government fails to act quickly to end attacks by Arab militias and allow humanitarian aid to reach displaced people.

Annan arrived in the capital, Khartoum, after visiting Sudanese refugees at a camp in Chad on a tour aimed at pressing President Omar el-Bashir's (search) government to end the 16-month conflict.

In particular, the U.N. chief wanted el-Bashir to make good on promises to disarm the Janjaweed (search), the militia blamed for attacks on thousands of black African villagers.

"My message is simple, violence must stop," Annan told reporters after meeting el-Bashir in Khartoum's heavily guarded military headquarters. "The Janjaweed must be stopped and a cease-fire must be respected by all."

U.N. officials and human rights groups have accused the Sudanese government of backing the Arab militias, engaged in a campaign to violently expel African farmers from the vast western region.

During tours of refugee camps inside Sudan and Chad, Annan said he learned firsthand of many human rights abuses, "including sexual violence against women."

But after Friday's talks, Annan said "now we have a commitment from President el-Bashir to remove all obstacles that face humanitarian action in Darfur."

U.S. Secretary of State Colin Powell also visited Sudan this week, and made clear to Khartoum leaders that the United States is only willing to wait a "few weeks" for the government to act, said Andrew Natsios, head of the U.S. Agency for International Development (search), who traveled with Powell.

"We're talking days, weeks, not months — not a month — to see whether or not they do what they said they would do," said Acting U.S. Assistant Secretary of States for African Affairs Charles Snyder, who joined Natsios on Friday in briefing the U.N. Security Council in New York.

Sudanese Foreign Minister Mustafa Osman Ismail told reporters that 6,000 soldiers and policemen would be deployed in Darfur to improve security, but he did not say when.

"The priority now is for security, then the return of the displaced persons, and this is to go hand in hand with the political settlement," Ismail said.

U.N. officials have called the situation the worst humanitarian crisis in the world, and Annan has said it "is bordering on ethnic cleansing."

Many Sudanese who have fled tell similar stories of airplanes dropping bombs and raiders on horseback who burn, kill and loot.

Thousands of people have been killed and more than a million forced from their homes, most taking shelter in makeshift camps with little access to clean water or proper sanitation.

The Sudanese government denies any complicity in the militia attacks and says the warring sides are clashing over land and scarce water resources.

The U.N. children's agency in Geneva said Friday that many young people from Darfur either had been victims of violence or scarred by witnessing violent acts, including rape and murder.

"I spoke with scores of children, who simply tell what they have seen — infants shot in front of them, parents gunned down in fields, mothers raped ... and people being forced to run for their lives with nothing," said Dan Toole, UNICEF's director of emergency operations.

Thousands turned out to see Annan at the Iridimi Camp in Chad, 44 miles west of the Sudanese border.

"All we want is peace so we can return," said Saleh Hamid Moubarak, a 57-year-old who is living at the camp, a mass of flimsy shelters made from sticks and plastic sheets. "Our children were killed, our belongings looted, our women raped."

The United States called on the United Nations to impose an arms embargo and travel ban on the Arab militias in a draft resolution submitted Wednesday to coincide with Powell's visit to Darfur.

The Justice and Equality Movement (search) and the Sudan Liberation Army (search), two rebel groups drawn from the region's African tribes, took up arms in February 2003 over what they regard as unjust treatment by the government in their struggle over land and resources with Arab countrymen in Darfur.

A cease-fire was signed April 8, but both sides accuse each other of violations.