President George W Bush has announced US emergency food shipments to ease the crisis in Sudan's Darfur region, urging Congress to approve $225m in aid.
Mr Bush said the US would "not turn away from the tragedy"
He also said he was sending his secretary of state to the UN Security Council to help speed up the deployment of UN peacekeepers to the region.
Sudan and the biggest rebel group signed a peace deal last Friday that could allow the UN to take over.
More than 200,000 people have been killed in the three-year conflict.
Calling the situation in Darfur a "genocide", President Bush said five aid ships would be urgently redirected to Sudan to provide extra help for the two million people displaced by the conflict.
DARFUR PEACE PLAN
Pro-government Janjaweed militia to be disarmed
Rebel fighters to be incorporated into army
One-off $300m transfer to Darfur
$200m a year for the region thereafter
Compensation for those forced to flee their homes
Regional government, if approved in a vote
He said: "These actions will allow the World Food Programme to restore full food rations to the people of Darfur this summer."
Money for the world's largest aid operation has been running out. Rations for May have been cut in half.
Mr Bush said: "Darfur has a chance to begin anew... America will not turn away from this tragedy."
The $225m deal will have to be cleared by Congress as part of an emergency spending bill that includes the Iraq war and Hurricane Katrina relief.
"I hope Congress will act swiftly on this true emergency," Mr Bush said.
He welcomed last week's peace deal between the government and the Sudan Liberation Army, aimed at ending three years of fighting in Darfur but said "the situation remains dire".
"We're still far away from our ultimate goal, which is the return of millions of displaced people to their homes," he said.
Mr Bush said Secretary of State Condoleezza Rice would address the UN Security Council on Tuesday.
"She's going to request a resolution that will accelerate the deployment of UN peacekeepers into Darfur," Mr Bush said.
"We're now working with the UN to identify countries that contribute those troops, so the peacekeeping effort will be robust."
Sudan's government had previously said no UN deployment could take place until there was a peace deal.
The UN's Jan Egeland was forced to flee a refugee camp
The rebels took up arms in 2003, accusing the government of discriminating against the black African residents of Darfur.
Pro-government Arab Janjaweed militias then launched a retaliatory campaign but the Sudan government denies backing them.
Some 7,000 African Union peacekeepers have failed to end the violence.
On Monday the UN's top humanitarian official, Jan Egeland, was forced to flee a camp for people displaced by the conflict after violent protests.
The trouble started during a march calling for foreign troops to be sent to protect the camps, when a woman said a translator belonged to a militia.
He escaped but another interpreter, who worked for the African Union, was set upon and killed a short while later.
The BBC's Jonah Fisher in Kalma says many of the protesters said they had little faith in the new peace agreement and only after an international force is deployed could they think about returning home.
The displacement of people has spurred the UN to warn of an impending disaster.
Aid organisations say the conflict has created one of the world's worst humanitarian crises.
More than 6m people across Sudan require food aid - more than in any other country.