The running mate of Kenyan presidential candidate Raila Odinga says the vote-counting process from Monday's election "lacks integrity" and should be stopped.
Kalonzo Musyoka spoke to reporters Thursday in Nairobi, while election officials continued to manually count ballots after a new electronic system broke down.
"There has been a total failure of the electronic vote transmission system, and we have evidence that the results we are receiving have actually been doctored," said Musyoka. "In some cases, total votes cast exceed the number of registered voters."
Close to half of the estimated votes were tallied by early Thursday, showing Uhuru Kenyatta leading Prime Minister Odinda by a 53 percent to 42 percent margin.
Officials say the final results could be released as early as Friday, but they legally have until Monday to finish the count.
The winning candidate is required to secure more than 50 percent of all votes cast or face a second-round vote in April.
The manual count has produced a far lower number of rejected ballots from a figure election officials gave late Tuesday - fewer than 40,000 compared to the nearly 500,000 from the earlier provisional results.
Despite some problems, international observers have described the vote as transparent and credible.
Kenyatta, son of Kenya's first president and one of Africa's wealthiest men, faces trial in the International Criminal Court for allegedly bankrolling death squads that carried out reprisal attacks against opposition supporters after disputed 2007 polls.
More than 1,000 people were killed in the violence while hundreds of thousands of others were forced to flee their homes.
About 14 million Kenyans were eligible to vote in the elections for president, parliament and other key offices. Both Odinga and Kenyatta have promised to respect the result of the vote.
Monday's election was mostly peaceful, although just hours before voting began, at least 13 people, including seven police officers, were killed along Kenya’s coast. Kenyan police arraigned three suspects in court Tuesday.
Election chairman Ahmed Issack Hassan said there were no reported incidents of violence during voting hours. He also said voter turnout appears to have been above 70 percent.