Protesters set fire to a government office building Wednesday, forcing workers to climb out windows as former U.N. chief Kofi Annan tried to resolve the dispute over Kenya's presidential election.
The melee started after police fired tear gas at stone-throwing youths during a memorial service organized by the opposition to honor those killed since the Dec. 27. election.
President Mwai Kibaki won a second five-year term, but the opposition and international observers say the vote tally was rigged. Some 685 people have been killed in riots and ethnic fighting.
During the memorial service, opposition leader Raila Odinga said Kenya's 40-plus tribes should not be at war with one another.
"This is a war between the people of Kenya and a very small bloodthirsty clique clinging to power," Odinga told about 800 supporters in a sports ground.
Just outside, young men were stopping cars, beating people and taunting police. Police initially held their fire but eventually responded with tear gas, some of which landed inside the sports ground and forced the mourners to flee. About 50 young men then set upon the government-owned telecommunications building, smashing windows and starting fires.
"We don't know what happened," Mary Bwire, a secretary at the office, told The Associated Press. "Suddenly there were stones everywhere. We all hid under tables."
She and several other workers crawled out ground-floor windows to safety.
Under pressure from Annan, Kenya's opposition later called off plans for a day of protests Thursday, a small victory on the former U.N. secretary-general's first day of mediation. Police have banned all demonstrations, and at least 24 people died in three days of protests last week. Most of the deaths were blamed on police.
"On the request of the mediation team we have called off the activities we had planned for tomorrow," said William Ruto, a leading opposition figure.
In Limuru, about 15 miles outside Nairobi, police fired at men with machetes who blocked the road and demanded to know people's ethnicity, Nancy Chumba, a witness, said by telephone. Two people were fatally shot, according to a police official who spoke on condition of anonymity because he was not authorized to talk to the media. Another two people were found dead in Nairobi's slums, police said.
Annan is the latest international figure to try to intervene in the standoff. The chairman of the African Union, Ghanian President John Kufuor, failed to persuade Kibaki and Odinga even to meet.
The fighting has pitted protesters against police, but there also have been clashes between members of Kibaki's Kikuyu ethnic group and other tribes.
Beatrice Michael Achieng, 35, was at a mortuary Wednesday that was the starting point of the opposition's memorial procession. She was collecting the body of her 13-year-old daughter, who was shot outside their home in a Nairobi slum.
"I think the protests should stop. I don't want to hear about Raila. I don't want to hear about Kibaki. My daughter is gone and we need peace," Achieng said. "I am feeling very bitter and angry at the police. I haven't eaten since the day my daughter died. She was my first born and I've even thought of hanging myself."
Both sides have accused the other of being behind the violence, with the government and opposition saying they will take each other to the International Criminal Court in The Hague, Netherlands.