The United States is welcoming the cease-fire agreement in the Darfur region in western Sudan and urging the parties to the conflict there to implement the truce immediately. A U.S. aid team is being sent to the area to assess humanitarian needs.

The cease-fire deal between the Sudanese government and two local rebel groups in Darfur was signed Thursday and is to take effect within 72 hours.

But the State Department is urging the parties to cease hostilities immediately and to facilitate delivery of humanitarian aid in the remote area, where nearly a million people have been displaced by the fighting.

Efforts to end the broader north-south civil war in Sudan were marked by numerous failed truce agreements. At a news briefing, State Department spokesman Adam Ereli noted there is intense international focus now on Darfur and that a failure by the sides to keep the cease-fire would not be without consequences.

"We are watching, and the international community is watching, and this is an opportunity for all those who signed this agreement to prove their good faith, and their good faith and their ability to carry through on commitments. And clearly failure to do that has implications," Mr. Ereli said.

Mr. Ereli said the United States will keep the situation in Darfur under "intense review" and will use all appropriate means to obtain information about what happens on the ground during the implementation process.

The spokesman stressed language in the agreement under which the parties are to "neutralize armed militias," and said this refers the Sudanese government-supported Arab militias, known as the Jingaweit, that have been "brutalizing" the local African population.

Thousands of people have been killed in the Darfur fighting and nearly a million people driven from their homes, including more than 100,000 refugees who have crossed into neighboring Chad.

Mr. Ereli said the United States has provided more than $53 million in relief assistance for Darfur since late last year, most of it food aid being distributed by the U.N.'s World Food Program.

He said the U.S. Agency for International Development is assembling a disaster assistance response team to go to the area and assess additional needs.

A senior U.S. diplomat took part in the Ndjamena talks, along with officials of the Chadian government, the European Union, the African Union and the United Nations.

The Darfur truce is to be in place for 45 days, though it can be renewed and contains provisions for outside monitoring and "unimpeded" humanitarian access.