US Secretary of State Colin Powell issued an ultimatum to Sudan of UN action unless it allows full aid access to more than one million refugees and disarms militias killing in the Darfur region.
Sudanese Foreign Minister Mustafa Osman Ismail said his government would combat the Arab militias in the remote region and improve aid access to refugees caught up in what the United Nations has called the world's worst humanitarian crisis.
US officials and human rights groups accuse Khartoum of arming and supporting the Janjaweed Arab militias to raid black African villages in Darfur in a campaign of ethnic cleansing.
Khartoum denies the charges, saying the Janjaweed are outlaws.
Some 10,000 to 30,000 people are estimated to have been killed in the Darfur crisis.
The United States called for the United Nations to impose an arms embargo and travel ban on Darfur's militias, but a new US-drafted Security Council resolution obtained by Reuters would not impose sanctions against the Khartoum government.