Kenyan President Uhuru Kenyatta appeared late Wednesday to be headed for re-election, while his opponent was charging that massive fraud had occurred in voting the day before.
Kenya's election commission said that with results from 96 percent of polling stations counted, Kenyatta led opposition leader Raila Odinga 54 percent to 44 percent.
Officials have up to a week to verify the results and announce a winner.
But Odinga alleged hackers had carried out a "massive and extensive" attack on the election commission's computer system and that the results announced so far were fraudulent.
'We caught them'
"What the IEBC [Independent Electoral and Boundaries Commission] has posted as results on the presidential elections is a complete fraud based on a multiplier that fraudulently gave Uhuru Kenyatta votes that were not cast," Odinga said. "The fraud Jubilee [Kenyatta's party] has perpetuated on Kenyans surpasses any level of voter theft in our country's history. This time, we caught them."
The head of the commission, Ezra Chiloba, responded, telling reporters, "We have not been able to find any attempts of hacking and our position is ... that our systems are intact."
Rafael Tuju, secretary-general of the Jubilee Party, dismissed Odinga's accusations as disingenuous and appealed for calm.
"These results are not coming from out of the blue. They are marked by facts, and you cannot claim that results are fake with respect to presidential and you welcome the areas where your governors and your members of parliament have won convincingly," Tuju said.
Kenyatta and Odinga have a deep rivalry. They ran against each other in the 2007 and 2013 presidential elections. After he lost in 2013, Odinga alleged that votes had been tampered with and challenged the result in court. The 2007 election was followed by violence fueled by ethnic divisions that killed more than 1,000 people.
Protest in Kisumu
Shortly after Odinga spoke Wednesday, several hundred protesters in his western stronghold of Kisumu burned tires and clashed with police, who fired tear gas.
Also, five men with knives stabbed people at a polling station in the town of Hola. Police shot and killed two of the attackers, and the other three escaped.
One report said that one person, a poll worker, had been stabbed to death. It was unclear who carried out the attack and why.
In addition to choosing a president, voters also decided on senators, governors, women's representatives of the national assembly, members of the national assembly, and members of the county assemblies.
Former U.S. Secretary of State John Kerry is part of the international election observation mission. He said the the long lines he saw at polling stations Tuesday was a sign Kenyan voters were committed.
"It's too early for us to draw any kinds of conclusions, so we're not. But, obviously, given what's happened in the past and given the stakes for the future, this is a very, very important election, and clearly the citizens of Kenya are taking it very, very seriously," Kerry said.
'Nothing bad has occurred'
Hellen Mazitoh, 32, a voter from the Githogoro slum in Nairobi, waited in line for well over seven hours, but said she wasn't complaining.
"Let me say, the election mood is good," she said. "People are voting. Once they vote, they are going home. Nothing bad has occurred. Nobody left. People are responding well."
Voter Emmanuel Musundi Wamukundi, 33, waited for more than four hours at his polling station in Nairobi. He said the lines were a bit disorganized in the beginning, but otherwise, things seemed to be running smoothly.
"I mean, it's patriotism. This is for my country, and I want to be involved in it," said Wamukundi. "I want my voice to be heard, and it's the only thing I can do to change things."
The electoral commission said heavy rain hampered voting in three parts of the country — Turkana North, Baringo and Samburu — and helicopters were required to airlift materials and polling officials.