Kenya's government and opposition party have agreed to write a new constitution within a year, a government negotiator has said.
Mutula Kilonzo told Reuters news agency that the parties had "reached agreement on a wide-ranging sphere of issues".
The deal comes after talks aimed at bringing an end to the post-election violence which has left at least 1,000 people dead.
Mr Kilonzo gave no further details about the contents of the deal.
The talks, led by former UN Secretary General Kofi Annan, have been seeking a resolution to the disputed elections held in December.
Kenyan President Mwai Kibaki was formally declared the winner, but supporters of opposition leader Raila Odinga and his Orange Democratic Movement (ODM) argued that the count was rigged.
More than 600,000 people have been displaced in the ensuing violence between rival ethnic groups.
The deal on a constitution could pave the way for a power-sharing agreement and possibly the introduction of a prime ministerial post in Kenya's political system.
Both the ODM and Mr Kibaki's Party of National Unity (PNU) have put forward power-sharing proposals.
Opposition leaders have not yet commented on the deal, which is likely to be only the first step in the complex negotiations.
The announcement comes shortly after US President George W Bush said he was sending Secretary of State Condoleezza Rice to support Mr Annan in the talks.
"There must be an immediate halt to violence, there must be justice for the victims of abuse and there must be a full return to democracy," Mr Bush said earlier today.