NAIROBI, Kenya — Kenya’s defeated presidential challenger, Raila Odinga, claimed yesterday to be a cousin of Barack Obama and said that they had discussed his country’s post-election violence.

Mr. Odinga, 63, said the U.S. senator’s father, from western Kenya’s Luo tribe, was his maternal uncle.

“He has called me to talk about the constitutional crisis in this country despite being in the middle of the very busy New Hampshire primary,” Mr. Odinga said. Mr. Obama’s spokesman, Robert Gibbs, confirmed that the senator spoke to the Kenyan opposition leader on Monday afternoon for about five minutes before going into a rally in New Hampshire.

The Democratic presidential candidate is also understood to have spoken to President Kibaki, whose victory in the December 27 election has been widely questioned.

Mr. Odinga’s claim to be a blood relative of the senator could not immediately be verified.

Mr. Obama’s father, also named Barack Obama, won a scholarship to a university in Hawaii, where he met and married Mr. Obama’s American mother. The two separated, and Mr. Obama’s father returned to Kenya, where he worked as a government economist until he died in a car crash in 1982.

The American Democrat visited Kenya in August and made a speech that was televised live in which he criticized the corruption and tribal politics that have dominated the country since its independence from Britain in 1963.

Over the past 10 days, Kenya has been rocked by tribal clashes that have left at least 600 people dead after Mr. Kibaki claimed victory and Mr. Odinga declared the vote had been rigged.

Mr. Obama’s uncle, Said Obama, said yesterday that his village, Kogela, in western Kenya, had been spared the violence.

If Barack Obama were in Kenya today, he would “work with the leadership to bring them to a roundtable and find a solution to the problems that have been ravaging the country,” his uncle said. Said Obama said his nephew “has proved to be a beacon of hope here and shown that, even in difficult circumstances, you can make it to the highest height of achievement with just determination and hard work.”

[Meanwhile, the Associated Press reported that Kenya’s president named half his Cabinet yesterday, angering opposition leaders who accuse him of stealing the recent election and undermining mediation attempts for a power-sharing agreement to end violence that has left more than 500 dead. In the hours after Mr. Kibaki announced his Cabinet appointments, police fired over the heads of youths who set up a roadblock of burning tires in the western town of Kisumu, according to a resident there. In Nairobi’s oldest slum, Mathare, a witness reported hearing the first gunshots in three days just an hour after the announcement.

Political violence in some areas since the East African nation’s disputed December 27 presidential election had deteriorated into clashes between other tribes and Mr. Kibaki’s Kikuyu, which has long dominated Kenyan politics and the economy.

Salim Lone, a spokesman for the party of the opposition leader, Mr. Odinga, repeated the party’s call for no demonstrations, saying it did not want to undermine African Union-mediated talks expected to begin Wednesday.

“We think that the announcement of the Cabinet was a slap in the face for all the effort that Kenyans and the international community is making to avoid the crisis,” Mr. Lone said.

Earlier yesterday, Mr. Odinga rejected an invitation from Mr. Kibaki for talks, calling it “public relations gimmickry” and charging the president with “trying to deflect attention from and undermine” international mediation.

One proposed solution has been for Messrs. Kibaki and Odinga to share power. But the Cabinet members announced by Mr. Kibaki, among them his vice president, included no portfolios for members of Mr. Odinga’s party.]