Rice's visit comes as George Bush, the US president, is on the second leg of his five-nation Africa tour.
Rice stepped up pressure on the parties by stressing that a resolution, through a power-sharing deal, would improve relations with the US.
"I want to be very clear: The current stalemate and the circumstances are not going to permit business as usual with the United States,'" she said.
"They need to share power and share responsibility for the governing of this country."
On the eve of Rice's visit, Kenya's foreign minister had strong words for anyone trying to force a deal on the government.
"We encourage our friends to support us and not make any mistake of putting a gun to anybody's head and saying 'either/or', because that cannot work," Moses Wetangula said.
"Even if we get visitors to help us in any way possible, the answer to the problem in Kenya lies with Kenyans themselves."
Rice said that US calls for a deal were "not a matter of dictating a solution to Kenyans," adding that pressure was coming from within Kenya and not from abroad.
Although Annan reported considerable progress in last week's talks, including agreement on an independent review of the disputed poll, most Kenyans are waiting for a breakthrough on the contentious "grand coalition" idea he has advocated.
Government officials have said the only power-sharing being considered is giving opposition members top jobs in ministries in Kibaki's cabinet.
But that proposal is unlikely to satisfy the opposition when talks resume on Tuesday.