Kenyan President Uhuru Kenyatta took what appeared to be an unassailable lead Wednesday in his bid for reelection, even as his opponent called the results fraudulent, raising fears of political violence after a bitterly contested race.

With 93 percent of the votes counted, Kenyatta led with about 54 percent, far ahead of opposition leader Raila Odinga at about 45 percent, according to the Independent Electoral and Boundaries Commission.

But Odinga called the results of Tuesday’s election “a complete fraud,” outlining an elaborate hacking scheme that he said significantly manipulated the outcome. According to Odinga, a hacker used the login information of a top election official, Chris Msando, who was mysteriously killed last month, to enter the country’s electoral database.

He told his supporters not to accept Kenyatta’s reelection. Sporadic, mostly small-scale demonstrations popped up in the capital, Nairobi, and in parts of western Kenya, and police fired tear gas to break up at least one protest in the city of Kisumu. Witnesses said that two demonstrators were fatally shot by police in Nairobi’s Mathare slum.

The hacker, Odinga said, “took control of the entire network” and altered the results.

Supporters of Kenya's opposition party shout slogans as they set fire to barricades in Kisumu on Aug. 9 during a protest of election count figures. (Kevin Midigo/Agence France-Presse via Getty Images)

The electoral commission said it was not prepared to dismiss Odinga’s claim outright. It also emphasized that the results released so far were provisional. Final results, which could be released in the next several days, will offer more substantiation, the commission said.

But election officials did not explain how the near-complete results already released online could differ significantly from a more formal tally. Amid the confusion, less popular presidential candidates accepted the results as accurate and conceded to Kenyatta.

“We shall go into that and find out whether or not [Odinga’s] claims are true,” Wafula Chebukati, the head of the electoral commission, said at a news conference.

Chebukati said the panel is calling for original voting materials “for purposes of knowing and verifying before we do the final announcement.”

Odinga, a former prime minister, has run unsuccessfully for president three times before. In 2007 and 2013, he alleged that the results were rigged. In 2007, the country was engulfed by post-election ethnic violence that left about 1,400 people dead.

Kenya has become one of Africa’s strongest economies and many consider it a pillar of stability in a fragile region. But its politics are still dominated by tribal loyalty, and elections bring with them the fear of violence.

Ahead of Tuesday’s vote, many people left the capital for less-volatile areas in the countryside. Msando’s death last month — and signs that he had been tortured — shocked the nation.

The vote itself was peaceful and seemingly smooth, with millions of people lining up nationwide and few major problems at polling stations, according to international election monitors.

At a news conference, Odinga urged his supporters to remain calm, even as he told them “not to accept these results.”

His running mate, Kalonzo Musyoka, added obliquely: “There may come a time when we need to call you into action.”

Officials from Kenyatta’s party urged Odinga to accept the outcome.

“Only one campaign could emerge victorious. We appeal to NASA [Odinga’s party] to stop calling results fraudulent,” Raphael Tuju, secretary general of Kenyatta’s Jubilee Party, told reporters. Tuju added that the results were not yet official.

When asked at a news conference how he knew about the hacking of the election database, Odinga said he could not reveal his source.

Many businesses were closed in some of Kenya’s major cities, including Nairobi and Kisumu, with residents remaining indoors, glued to radios and televisions. In Mathare, one of Nairobi’s largest slums, Odinga supporters took to the streets Wednesday morning, and there was a brief surge of violence when a unit of police officers arrived.

“Every time we vote in Kenya, our votes are stolen,” said Akal Nicholas, a resident of Mathare and an Odinga supporter. “We can’t keep allowing this to happen. We have to do something.”

Rael Ombuor contributed to this report.