Former United Nations chief Kofi Annan is expected to reveal details Friday, of an agreement between Kenya's government and the opposition aimed at ending the country's political crisis.

He said Thursday that the two sides had signed a deal.

Mr. Annan has been serving as chief mediator in talks on ending violence that erupted after Kenya's disputed presidential election in December.

Also Thursday, a government negotiator said the two sides agreed to write a new constitution within the next year. However, he said they have not agreed on how to structure the government.

More than 300,000 people have been displaced and more than 1,000 have died in clashes since the opposition accused President Mwai Kibaki of stealing the December 27 election.

In other developments Thursday, President Bush announced he is sending Secretary of State Condoleezza Rice to Kenya to demand an end to the violence.

Secretary Rice will accompany Mr. Bush on his upcoming trip to Africa. Mr. Bush said he has asked Rice to support Mr. Annan's mediation efforts and call for a full return to democracy.

A spokesman for Kenyan opposition leader Raila Odinga says Mr. Bush's decision to send the secretary of state to Kenya is an encouraging sign that could help stop the violence.

Some information for this report was provided by AFP and  AP.