Kenya's opposition leaders have called off a mass rally that had been scheduled for Thursday in Nairobi to protest alleged vote rigging in last week's presidential election.  Before the march was called off police used tear gas and water cannons to block protesters from reaching the city center.  As VOA Correspondent Alisha Ryu reports from Nairobi, the cancellation of the march is not likely to calm tribal and ethnic tensions that have fueled the worst unrest the country has seen in decades.

A top official in the opposition Orange Democratic Party (ODP), William Ruto, says the rally was called off because the party and its supporters did not want violence to overshadow the demonstration.

Nairobi's normally-congested downtown was nearly deserted in anticipation of expected clashes between protesters and government security forces in nearby Uhuru Park, where the opposition said a million people would gather to express their outrage over the December 27 vote.

The government of President Mwai Kibaki banned the rally earlier this week and vowed to crack down on anyone threatening law and order.  Even before dawn on Thursday, hundreds of paramilitary soldiers and baton-wielding riot police began arriving to form a human cordon around the public park.

Smaller groups of riot police were also deployed near opposition strongholds in the city to prevent supporters of opposition leader Raila Odinga from making their way to the downtown area.  Odinga lost the election to Mr. Kibaki by a narrow margin in the disputed vote.

But the heavy police presence failed to deter thousands of Raila Odinga supporters from trying to attend the anti-government rally.

Protesters poured out of Nairobi's sprawling Kibera slum and other shanty towns, shouting that if the government wanted to stop the week-long post-election violence, which has killed more than 300 people in Kenya and has displaced as many as 100,000 others, President Kibaki must resign.

"No Raila, no peace!  No Raila, no peace!  And we are ready to die, especially the youths," said one protester. "We are ready to die!  Kibaki must go!"

Police immediately responded with force, firing tear gas and water cannons to disperse crowds.  Near Kibera slum, VOA was present when a truckload of about 60 riot police arrived and fired live rounds at a large group that had gathered by the road.   

Running away from the mayhem, Johana Owoth, 25, a member of Mr. Odinga's Luo tribe, accused Mr. Kibaki's government of using force to silence and oppress Kenyans who are not from the president's ethnic Kikukyu tribe, which has long dominated the country's politics and business.

"What violence is going on right now?  We are peacefully demonstrating while they are throwing tear gas and bullets," he said.  "The government is not sensitive to the cries of Kenyans."

Amid international calls for reconciliation, South African Nobel peace laureate Desmond Tutu flew to Nairobi and held talks with Raila Odinga.  Details of the meeting are not yet known.

Odinga says he would accept international mediation.  To stem the political crisis, he also proposes setting up a power-sharing government to prepare for fresh elections.