Sudan's ambassador to the United Nations is challenging the United States to send its troops to Darfur, if it thinks genocide is occurring in the region.

Elfatih Mohamed Erwa made the challenge on Tuesday, including both the U.S. Congress and the Bush administration in his invitation.

"If it is really a genocide, they should be committed to send troops," Erwa said of the conflict in Sudan's western region, where tens of thousands have been killed and raped in recent months as Arab militias allegedly backed by the government raided villages occupied by non-Arab ethnic Africans.

"This is why I don't think they're genuine about its being genocide."

This spring, the United Nations called the violence in Darfur the world's worst current humanitarian crisis, partly because of desperate conditions in the huge refugee camps the conflict has spawned.

In September, U.S. Secretary of State Colin Powell was the first high-ranking official from a head of state to label the crisis "genocide." He called on the Sudanese government to show it is serious about stopping the Janjaweed militiamen from harming more residents of Darfur.

Asked whether his government would really welcome U.S. troops, Erwa told reporters: "I won't say that I welcome them because I don't have the authority to say that, but if they want to [send troops], let them talk to us."

The challenge was a relatively safe one to make. Both President George W. Bush and Democratic presidential challenger John Kerry ruled out sending American forces to the conflict zone during last week's campaign debate.

"It's a curious idea, but I don't think it has a future," John Danforth, the American ambassador to the UN, said Wednesday in reply to Erwa's statement.

Because American troops are already over-committed in Iraq and other places around the world, Danforth said the U.S. will let a pan-African contingent of troops handle the Darfur crisis. He added that the Bush administration strongly supports those efforts.