U.S. Secretary of State Colin Powell says that a hard-won agreement to end the fighting between Sudan's government and southern rebels could provide momentum for settling the conflict in Darfur, in western Sudan. Powell was in Kenya's capital to represent the United States at Sunday's signing of the peace deal settling the conflict in southern Sudan. A regional grouping, the United States and other countries helped push the two sides to end the fighting. Among those expected at the ceremony are African Union Chairman and Nigerian President Olusegun Obasanjo, Kenyan President Mwai Kibaki, Ugandan President Yoweri Museveni and Arab League Secretary General Amre Moussa. "I think this agreement stands on its own merits," Powell said at a news conference with the top rebel leader from the south, John Garang, and Sudan's vice president, Ali Osman Mohammed Taha. "It brings a war to an end, but there are other wars taking place ... I think this gives us a basis now to redouble our efforts in Darfur," Powell said.