The clashes broke out shortly after President Uhuru Kenyatta was declared the victor of the disputed election with 54.27 percent of votes, beating Odinga who scored 44.74 percent, according to the election commission.
Electoral commission Chairman Wafula Chebukati has rejected the opposition's argument, however, saying the evidence they provided is "obviously and plainly falsified and contains elementary errors".
At this crucial moment, he and his National Super Alliance (NASA) must also step up to this call for transparency: if they can not swiftly substantiate their allegations that the election was hacked and "most" of the official results already published by the IEBC are false, they should concede defeat and thereby contribute to strengthening Kenya's democracy.
While Kenyatta holds a strong lead with nearly all polling stations counted, supporters of Odinga say an unofficial tally shows he won. Many Kenyans fear a repeat of violence that followed the 2007 election. "There was no serious security cases reported; I therefore urge Kenyans to remain calm", Matiangi said.
He first alleged that a hacker had gained access to the electoral commission's database and then accused the commission of concealing the actual results, which Odinga said proved he was the victor.
Why are Kenya's elections so bitterly contested?
Mr. Obasanjo said it would not be in anybody's interest in Kenya to have to resort to the ICC again. We as Kenyans need development not violence.
They say the unrest broke out after Kenya's election commission announced that President Uhuru Kenyatta had won a second term, defeating Odinga.
"Nobody should think this is the end of the matter", he said.
In 2007, tallying was halted and the incumbent president declared the victor, triggering an outcry from Odinga's camp and waves of ethnic violence that led to International Criminal Court charges against Kenyatta and his now-deputy, William Ruto.
James Orengo, another senior NASA official, called the election process a "charade" and a "disaster".
"The results published by the electoral commission are a fraud", John Mbadi, a member of Odinga's opposition coalition National Super Alliance, reiterated during a press conference on Friday.
They ruled out the possibility of seeking legal redress after the commission insisted on announcing the victor before addressing their concerns.
Angry protests had erupted in opposition strongholds in Nairobi and the western city of Kisumu, an opposition stronghold on Wednesday, with demonstrators burning tyres in the streets.
The electoral commission admitted that hackers had tried to access its database, but said they did not succeed. "The failure to announce results at the constituency centers raises so many questions about transparency".
Police shot dead one protester in Nairobi.
Polling stations opened at 6am and closed at 5pm but many were in the queues as early as 2am. At least three people were killed.
Protracted turmoil could derail an economy that's grown an average of 5.7 percent a year since Kenyatta took power in 2013, and threaten its reputation as a top African investment and tourist destination.
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