The World Bank said the violence could threaten Kenya's impressive economic gains and harm neighbouring countries that depend on it as a business hub.
INVESTIGATION
Warning that Kenya was "quickly degenerating into a catastrophe of unimaginable proportions," Attorney General Amos Wako said both sides should agree on an independent person or body to carry out "a proper tally" of votes from the election.
"Such an exercise will go a long way in assuaging the inflamed passions of people," Wako said.
But he added that while the tally should help political mediation, only a court could overturn Kibaki's win.
From dawn, riot police were out in force as the city, virtually deserted by workers, was transformed into a battleground. Several columns of protesters surged out of slums towards the city-centre, singing the national anthem, chanting "Peace" and waving twigs and leaves.
When confronted with police lines, they at first sat or kneeled in the road. As tempers rose, they began burning cars and buildings.
Police responded with teargas and water cannons, firing in the air when the crowd knelt down and taunted: "Kill us all", a Reuters witness said.
Protester Julius Akech yelled: "This is dictatorship now."
The daily violence has shocked world leaders and choked supplies of fuel and other goods to a swathe of central Africa.
Pro-Kibaki legislators called for Odinga and others to be charged by the International Criminal Court with "ethnic cleansing and genocide".
International figures urged talks in a nation previously known as an African peacemaker rather than a disaster zone.
"This is a country that has been held up as a model of stability. This picture has been shattered," said South African Nobel peace laureate Archbishop Desmond Tutu, in Kenya to try to start mediation. "This is not the Kenya that we know."
In rural areas, the unrest has touched off deep ethnic tensions. In an area where 30 members of Kibaki's Kikuyu tribe were killed in a church torched by a mob, young men with machetes manned roadblocks and hunted their enemies.
Protesters almost overwhelmed police as they tried to enter the centre of Kisumu, an opposition stronghold in western Kenya already ravaged by riots and looting.
Kikuyus, long dominant in politics and business, were targeted in initial clashes, but revenge killings -- including some by the Kikuyu Mungiki criminal gang -- are on the rise.
While most foreign observers said the vote fell short of democratic standards, Uganda's President Yoweri Museveni was the first African leader to send congratulations to Kibaki.
But at the same time, Kampala closed its borders. Hundreds of refugees, however, were allowed to cross into Uganda, taking shelter in schools and churches.
Kenyan media united in pleas for peace, with every major newspaper running the same front-page headline: "Save Our Beloved Country".
