KISUMU, Kenya — Thousands of machete-wielding youths hunted down members of President Kibaki’s Kikuyu tribe yesterday in western Kenya’s Rift Valley, torching homes and buses, clashing with police, and blocking roads with burning tires.

Witnesses described seeing two people pulled from cars and stoned to death, while another was burned alive in a minibus — the latest victims of a month of escalating violence triggered by a disputed presidential election. The death toll has soared over 800.

Mr. Kibaki has said he is open to direct talks with an opposition leader, Raila Odinga, who is from the Luo tribe, but that his position as president is not negotiable. Mr. Odinga says Mr. Kibaki must step down and only new elections will bring peace.

“The road is covered in blood. It’s chaos. Luos are hunting Kikuyus for revenge,” a journalist for independent Kenya Television in Kisumu, Baraka Karama, said. There was no sign of relief from international mediators trying to persuade politicians to resolve the crisis that has erupted over Mr. Kibaki’s re-election in December 27 balloting that international and local observers say was marred by a rigged vote tally.

Mr. Kibaki has said he is open to direct talks with Mr. Odinga, but that his position as president is not negotiable. Mr. Odinga says Mr. Kibaki must step down and only new elections will bring peace.

Columns of smoke rose from burning homes in Kisumu, according to journalists who flew into the town.

“We wish to find one, a Kikuyu. … We will butcher them like a cow,” said David Babgy, 24, who was among 50 young men stopping buses at a roadblock of burned cars and uprooted lamp posts.

But the only deaths reported there yesterday, apart from the burned bus driver, were people shot by police whom human rights groups accuse of using excessive force.

In Nakuru, provincial capital of the Rift Valley, 64 bodies were counted yesterday at the morgue, a worker said asking that his name not be used because he was not authorized to speak to the press. Over the weekend, a gang of Kikuyus chased 19 people through a slum in Naivasha and they were trapped in a shanty that was set on fire, police commander Grace Kakai said. The victims were Luos. At least three other people were killed in the town over the weekend, district commissioner Katee Mwanza said.

As youths set buses ablaze at Kisumu bus station yesterday, police used tear gas, then opened fire. A morgue attendant said one man whose body was brought in had been shot in the back of the head. A school janitor also was killed by a stray bullet fired by a police officer, a teacher at Lion’s High School, Charles Odhiambo, said.

Fred Madanji, a gas station attendant, said he saw two other “protesters” shot in the back and killed as they ran from police.

In villages around the town of Eldoret, gangs of Kalenjin youths hunted Kikuyus and killed six. Four were slashed with machetes and two were pulled from the cars and stoned to death, according to witnesses.

A military helicopter tried to land at the village of Cheptiret but was prevented by youths who set grasslands ablaze.

Naivasha, Kenya’s flower-exporting capital on a freshwater lake inhabited by pink flamingoes, became a war zone Monday where some 2,000 people from rival tribes faced off, taunting each other with machetes and clubs inset with nails.