Thousands of Sudanese refugees crowded U.S. Sen. Barack Obama on Saturday as he visited their camp in eastern Chad and delivered a single message: Bring in the United Nations.

The refugees told Obama an international peacekeeping force is the only hope they have of returning to their normal lives in Sudan's western region of Darfur. Some carried banners held up on sticks demanding U.N. action.

A man who identified himself only as Musadigo said he has been living in the refugee camp, which is home to about 15,000 people, since fleeing his home three years ago. Chad now hosts more than 200,000 refugees from Darfur.

"We want the U.N. force," he said. "We won't be able to go home without the U.N."

Sudan rejected as "illegal" a U.N. Security Council resolution passed Thursday paving the way for the replacement of 7,000 ill-equipped African Union peacekeepers in Darfur with more than 20,000 U.N. troops and police.

The conflict in Darfur began in 2003 when ethnic African tribes revolted against the Arab-led Khartoum government. The government is accused of unleashing Arab militiamen known as janjaweed who have been blamed for widespread atrocities.

About 200,000 people have died and some 2 million have been displaced by the conflict.

A peace deal in May signed by the government and one of the ethnic African rebel groups operating in the region has had little effect on the conflict.

After his 90-minute visit to the camp, about 466 miles east of the Chadian capital N'djamena, Obama said the U.S. should take a more active role in pushing Sudan to accept a U.N. peacekeeping force.

"My overarching sense is ... the need to get a U.N. protective force on the ground," he said.

Obama suggested the U.S. needs a special envoy to focus on the issue and said the U.N. might possibly have to move in without Sudan's permission.

Obama met with a group of women at the camp to talk about their experiences. He also met with camp leaders who said they ultimately want compensation for losses they have suffered and want to see the janjaweed brought to justice.

Obama, the only black U.S. Senator, is winding down his trip to Africa, which began Aug. 18 in South Africa. Obama's father was a native of Kenya.