NAIROBI, Kenya — Protests and riots convulsed Kenya on Sunday as the incumbent president, Mwai Kibaki, was declared the winner of a deeply disputed election and, minutes later, took the oath of office in a hastily convened ceremony at his residence.
Almost immediately, gunshots were heard throughout Nairobi, the capital, and dark plumes of smoke rose from shantytowns that are strongholds of Raila Odinga, the populist challenger. Kibaki appealed for calm but ordered television stations to suspend all live broadcasts, and police and heavily armed paramilitary units fanned out by the truckload across the city.
Clashes between rival camps were reported in the coastal city of Mombasa as well as the western towns of Kisumu and Kisii, both Odinga strongholds. Police said at least 15 people had been killed throughout the country since Saturday in election-related violence.
The events shattered Kenya's reputation as a haven of stability in turbulent East Africa, and marked a stunning reversal for Kibaki, 76, whose election five years ago was hailed by most Kenyans as a fresh start after the long, scandalously corrupt rule of Daniel Arap Moi.
Odinga, who had called for his supporters to remain calm in the days leading up to Thursday's vote, was not going quietly. His campaign called supporters to a rally Monday in central Nairobi for what was billed as a "parallel" swearing in.
The final vote count from Kenya's election commission - a nominally independent body - gave Kibaki an edge of 231,728 votes out of an estimated 11 million cast.
But Odinga's campaign said it had evidence that election officials in Nairobi had inflated Kibaki's tally by some 300,000 votes. They cited several vote counts from polling places in the central Mount Kenya area, a Kibaki stronghold, that exceeded the number of eligible voters in those constituencies.
Sunday's announcement came after lengthy delays in the reporting of results from the central region, which fueled speculation that Kibaki's campaign was trying to rig the ballot count, a charge the campaign denied.
Western election observers acknowledged a flawed result but urged Kenyans to accept it.
"The election commission, despite the best efforts of its chairman, has not succeeded in establishing the credibility of the tallying process to the satisfaction of all parties and candidates," said a statement from the chief European Union election observer, Alexander Graf Lambsdorff.