WASHINGTON, Feb 4 (Reuters) - Resolving the conflict in Kenya has a "long way to go," but negotiations between Kenya's government and the opposition were a start, White House national security adviser Stephen Hadley said on Monday.

Kenya's government and opposition begin detailed negotiations on Tuesday to try to end political and tribal conflict that has killed at least 900 people and brought one of Africa's brightest economies to its knees.

Under the mediation of former U.N. Secretary-General Kofi Annan, the two sides agreed on Monday on immediate steps to help the hundreds of thousands displaced by the violence and said they would start work on the political impasse.

U.S. diplomatic efforts were also underway, with an objective "to put pressure on both leaders to recognize what their dispute is doing to their country and to agree, if you will, to a time out, an agreement between the two sides that will stabilize the situation," Hadley said.

The goal is to have the leaders call on followers to not resort to violence, allow humanitarian assistance in and reach a point where elections could be held, he said at the Carnegie Endowment for International Peace.

"Many people believe that to go to elections now would not be a prescription for bringing stability," he said.

"I think we have a long way to go," Hadley added.

"It is a great tragedy. This is a country that we have all looked to as a model. It has fallen on hard times," he said.

President George W. Bush will travel next week to Africa, including neighboring Tanzania, to highlight efforts to boost economic development and fight AIDS and other diseases.

He will also visit Benin, Rwanda, Ghana and Liberia during the Feb. 15 to Feb. 21 trip. (Reporting by Tabassum Zakaria; editing by Todd Eastham)