NAIROBI, Kenya — Kenya's president threatened a tough crackdown Monday as rioters rampaged for a third day to protest what they called his sham re-election _ a bloody convulsion threatening what has been East Africa's most stable and prosperous democracy.
At least 135 Kenyans were reported killed in violence that flared from the shantytowns of Nairobi to resort towns on the sweltering coast. Opposition leaders set the stage for more turmoil by calling for a million people to rally against President Mwai Kibaki.
In the slums of Nairobi, rioters waved machetes and shouted "Kibaki must go!", while police beat protesters with clubs, fired off tear gas and shot live bullets in the air. Much of the country was at a standstill, with shops closed and many people hunkered inside their homes.
"We are ready to die and we're ready for serious killings," 24-year-old James Onyango, who lives in Nairobi's Kibera slum, told The Associated Press as homes and shops around him burned.
While there are no strong policy differences between the two camps, the bloodshed exposed tribal resentments that have long festered in Kenya, where Kibaki's Kikuyu people _ the largest group _ are accused of turning their dominance of politics and business to the detriment of others. Political loyalties are often tribal-linked, and ethnic gangs were reported attacking rival groups.
The opposition candidate, Raila Odinga, a member of the Luo tribe, called for 1 million people to march Thursday on the capital's Uhuru Park, where protesters seeking multiparty democracy massed in the early 1990s.
"We are calling for mass action," said Odinga, who led Kibaki in opinion polls before Thursday's ballot as well as in early election returns until his lead suddenly evaporated as official figures came out over the weekend. "We will march wearing black arm bands because we are mourning."
Kibaki, in a New Year's message to Kenyans, called "for healing and reconciliation," but he warned that his government would "deal decisively with those who breach the peace by intensifying security across the country."
Three police officers independently told AP journalists that they had been ordered to shoot to kill to stop rioters. A government spokesman denied such an order was given.
Teams of riot police deployed in the capital's Kibera and Mathere shantytowns, blocking people from marching on the largely deserted downtown.
In one neighborhood, a woman and her four young children ran from their home retching after police fired tear gas into the building.
"We were just hiding from the shots," said Dorothy Nyangasi, frantically pouring water over the eyes of her 6-month-old son.
Other people said they had not been able to find food since shops closed Thursday for the election. One woman shouted "Hungry! Hungry!" at passing journalists.
Ethnic fighting was evident in Nairobi's sprawling slums, where the neighborhoods are often divided along tribal lines. Kenya's Red Cross said that many of the dead were killed in ethnic clashes and that gangs were even checking on the tribal affiliations of Red Cross workers trying to help the injured.
Riots also raged in opposition strongholds in western Kenya, the tourism-dependent coast and the Rift Valley. In the port city of Mombasa, protesters looted shops and shouted "No Raila, no peace!", using the first name of Odinga, whom they support. The death toll across the country stood at 135, based on accounts from police, morgues and witnesses.
Odinga appealed to his supporters not to "ethnicize" the disputed election result, and he compared Kibaki to a military dictator who "seized power through the barrel of the gun."
Allegations of rigging were fueled by the fact that the opposition won most of the parliamentary seats in Thursday's vote.
The U.S. government, which has allied with the Kenyan government against Islamic militants in the region, joined others in questioning the validity of official results Sunday that declared Kibaki the election winner.
The State Department expressed serious concerns about what it called irregularities in the vote count. Tom Casey, deputy spokesman at the State Department, suggested the United States was not ready to recognize any winner.
"I am not offering congratulations to anybody because we have serious concerns about the vote count," he said. "What's clear is that there are some real problems here and that those need to be revolved in accordance with their constitution and in accordance with their legal system."
The U.S. Embassy in Kenya warned all Americans in the country to remain vigilant and aware of their personal security in light of the unrest. It encouraged all U.S. citizens to remain in place, saying security throughout the country is unpredictable.
The European Union also questioned the outcome.
"We have doubts about the accuracy of the presidential results," said Alexander Graf Lambsdorff, the chief European Union election monitor.
Former colonial ruler Britain said it shared those concerns and warned against all but essential travel to affected areas of Kenya.
The human rights group Amnesty International said it was concerned about reports that dozens had been killed in the post-election protests, "many by police bullets." It called on the government to establish an independent, impartial inquiry into the killings.
"Those responsible for human rights abuses should be brought to justice without undue delay," said Amnesty Africa Program Director Erwin van der Borght. "The government should ensure its security forces comply with international standards on the use of lethal force against demonstrators."
he violence, Odinga's resolve and the cool international response to his victory could put pressure on Kibaki, 76, to find a way to compromise with his opposition.
His main differences with Odinga stem more from personality than policy, with both seen as warm to the United States. Odinga is a flamboyant 62-year-old businessman who casts himself as a champion of the poor, while Kibaki is an understated, lifelong politician seen as the embodiment of Kenya's old guard.
Kibaki was sworn in almost immediately after the results were announced Sunday. Within minutes, the slums exploded into fresh violence, tainting a vote that initially was praised as calm and orderly.
If Kibaki had lost, he would have been Kenya's first sitting president to be ousted at the ballot box.
He won by a landslide in 2002, ending 24 years in power by the notoriously corrupt Daniel arap Moi. But Kibaki's anti-graft campaign has been seen as a failure, and the country still struggles with tribal divisions and widespread poverty.
Many Kenyans are poor even though their country is one of the most developed Africa, with a booming tourism industry and one of the continent's highest economic growth rates, averaging 5 percent a year.
Alex Busisa, a resident of Nairobi's Kibera slum who was shot in the stomach during the riots, said the violence is just another example of how the poor suffer.
"Life is more precious than power," he said. "But it is the man on the ground who suffers like me."
Associated Press writers Katharine Houreld and Tom Maliti contributed to this report.