Scattered violence has broken out in Kenya, amid delays in vote counting for what is shaping up to be the closest presidential race in the country's history. Partial results from Kenya's presidential elections show opposition candidate Raila Odinga is leading incumbent President Mwai Kibaki. Vote tallies released Saturday from 189 of 210 constituencies put Mr. Odinga ahead with 4.3 million votes to Mr. Kibaki's 4 million.  Nick Wadhams reports from VOA's Nairobi bureau. 

Impatience with the delays in announcing a winner in Kenya's presidential vote boiled over into violence between supporters of opposition candidate Raila Odinga and incumbent President Mwai Kibaki in the Mathare slum in Nairobi.

Two days after the polls, the latest results gave Odinga a slight edge over President Kibaki. Just 21 of Kenya's 210 constituencies remain to be counted, including parts of Nairobi and strongholds of Mr. Kibaki. For that reason, the electoral commission has not declared a winner. People angry with the delays have looted shops, burned tires in the streets and smashed car windows.

Thursday's presidential and parliamentary vote had earlier been seen as a success, because voter turnout was high and several lawmakers tainted by corruption were voted out of office. But events took an ominous turn on Saturday and the delays have led to allegations of vote-rigging.

Kennedy Ajowi, an Odinga supporter in downtown Nairobi, says he fears that the electoral commission is delaying results to give Kibaki's team time to fabricate votes for its candidate.

"From the look of things he has been defeated already," he said. "There's no mistaking it. They are delaying so that they compare the number of votes remaining, so that they can compare, and then they shore them up to cover up whatever the balance."

Despite the delays, Odinga declared victory based on his party's own tally. A member of Odinga's inner circle, Musalia Mudavadi, convened a news conference and called on Kibaki to step down.

"In view of the growing anxiety and restlessness in the country over the extended delay in releasing the presidential results by ECK, we now call upon the outgoing president to acknowledge and respect the will of the Kenyan people and concede defeat," said Mudavadi. "We further call upon him to direct his officers to begin the process of a smooth transition."

Mr. Kibaki's Party of National Unity has condemned the opposition's declaration of victory, and is demanding that Kenya wait for the official results. It maintains that Mr. Kibaki is leading in the polls.

Even after the opposition declaration of victory, Kenya's electoral commission continued to read out results.

U.S. Ambassador Michael Ranneberger appealed for calm, and Kenyan police blocked off roads to downtown Nairobi, making the city center a ghost town.

The violence and delays are leading some electoral observers to revise reports that had been expected to declare Thursday's vote free and fair.

The head of the European Union observer mission, Alexander Graf Lambsdorff, said some of the delays raised questions, but he also said there was no direct evidence of rigging so far.

"The delays we are all witnessing have been sharply criticized," he said. "They are clearly regrettable. They have rendered the announcement of the result of the presidential election impossible, while the tension in the population is rising. We do not now feel it is appropriate to make a judgment about an electoral process, which is clearly not yet over. It is clear that as the tallying process goes on, the delays are leading to mistrust and suspicion."

The head of the electoral commission, Samuel Kivuitu, now says he will demand final results by Sunday, or be forced to take action. But Kivuitu said even he had no idea why some areas had not reported in. He said phones were switched off at places where officials were tallying the polls.