NAIROBI, Kenya – Opposition supporters hurled stones, overturned kiosks and set them ablaze Thursday, but riot police beat them back with tear gas and water cannons in another day of tribally charged chaos after Kenya’s disputed presidential election.

Opposition leaders were forced to call off what had been billed as a “million-man march” after police and soldiers blocked access to Uhuru Park, a large public plaza whose name means “freedom” in Swahili. But supporters vowed to continue violent protests until the president, Mwai Kibaki, stepped down for allegedly stealing last week’s election.

There were few deaths reported in the protests. But Kenya was slipping deeper into uncertainty as Kibaki and challenger Raila Odinga rejected international calls for a political compromise to end the worst ethnic bloodletting in decades in this once-stable African nation.

Kibaki claimed a second five-year term despite credible reports of fraud in the ballot count from the vote Dec. 27. The outcome has sparked a nationwide wave of violence directed mainly at Kibaki’s tribe, the Kikuyu, whose control over politics and business long has fueled resentment among many of Kenya’s 41 other tribes.

Human rights groups say that Odinga supporters – including many from his own tribe, the Luo – are killing Kikuyus. The death toll so far is 300, according to estimates by rights groups, and 200,000 people have been forced to flee their homes, the Kenya Red Cross Society said.

Archbishop Desmond Tutu of South Africa arrived in Kenya to serve as a mediator. He said after talks with Odinga that Odinga was willing to negotiate.

In public, however, Odinga continued to call for Kibaki’s resignation.

“You want me to share power with a thief?” he said.