Supporters of Kenyan opposition leader Raila Odinga have said an unofficial tally shows he won the country’s presidential election despite a provisional official result that puts incumbent Uhuru Kenyatta in the lead.

Although most of the East African nation was calm after Tuesday’s vote, scattered clashes broke out between police and opposition supporters.

The uncertainty has left Kenya in political limbo, as its people await final results that they hope will dissipate tensions over vote-rigging allegations and preserve the long-term stability that has made the country a commercial hub.

Odinga supportersSupporters of Kenyan opposition leader Raila Odinga demonstrate in the Kibera area, blocking roads with burning tyres in Nairobi (Khalil Senosi/AP)

Opposition official Musalia Mudavadi claimed to have “complete data” from election commission servers showing Mr Odinga with a lead of several hundred thousand votes over Mr Kenyatta, contrary to results on the commission’s website that put the president more than a million votes ahead.

The opposition has received information from “confidential” sources in the election commission that indicates “the actual presidential election results contained in their database,” Mr Mudavadi said. He said there was a “serious attempt to try to either doctor or alter the final results”.

Mr Odinga, a former prime minister who has run unsuccessfully for president three times before, said hackers infiltrated the commission’s computer system and manipulated results against him.

Raila OdingaKenyan opposition leader and presidential candidate Raila Odinga says hackers have fixed the election result (Jerome Delay/AP)

Commission chairman Wafula Chebukati said a hacking attempt was made but it failed. Election officials are painstakingly trying to confirm their provisional results showing Mr Kenyatta in the lead with checks of documents from polling stations nationwide. The election commission has until August 15 to release the final tally.

“The long wait is leading to tension,” said political analyst Hezron Mogambi. “We are supposed by now to have had results, but the delay has been caused by the fact that the opposition had complaints about the system of transmitting results.”

Clashes between police and opposition supporters erupted in a Nairobi slum. Police fired on rioters in Kawangware, a poor area of the capital, according to an Associated Press photographer. One wounded man was carried away by protesters who said police shot him. Demonstrators also burned tyres in Kibera, another Nairobi slum.

NairobiRiot police fire tear gas towards protesters throwing rocks during clashes in the Kawangware slum of Nairobi (Ben Curtis/AP)

Violence also broke out in Garissa county, where opposition supporters demonstrated against the announcement of a ruling party candidate as the winner of a gubernatorial race. Police tried to restore calm after part of the town’s market was burned by arsonists, said a regional official, Mohamud Saleh.

At least three people were shot and killed in confrontations between security forces and opposition supporters in several areas of Kenya on Wednesday.

International observers said they have not noted any signs of interference with the vote and appealed to Kenyans to be patient.