At least 24 people have been killed by police gunfire since Tuesday's election, said the Kenya National Commission on Human Rights, which monitors government institutions. It appealed to senior officials to urge police to stop using live ammunition against civilians.
As rioting continued the day after President Uhuru Kenyatta won a second term in a vote the opposition claims had been rigged, an anguished father said his 9-year-old daughter was killed by a stray bullet while playing with friends.
Kenyan police shot and killed two people during riots by opposition supporters on the outskirts of Kisumu, a city where opposition leader Raila Odinga has strong support, according to Leonard Katana, a regional police commander. Another five people were injured by gunfire in Kisumu, Katana said.
The government should stop "the random killing of our people," Odings's brother Oburu Odinga said. The government accused "criminals" of taking advantage of the tense election period to loot and destroy property.
In Nairobi slums loyal to Odinga, police opened fire to disperse protesters who blocked roads and set up burning barricades. Associated Press photographers saw police charging demonstrators and firing live rounds and tear gas in the Mathare area.
Wycliff Mokaya told The Associated Press his 9-year-old daughter was killed by a stray bullet while on their third-floor balcony in Mathare.
"I was watching her play with her friends when she suddenly fell down," Mokaya said. "She was my only hope."
A mortuary official said nine bodies with gunshot wounds were brought to the Nairobi morgue from Mathare. The official spoke on condition of anonymity because he is not authorized to speak to the media.
Protesters, some with rocks or sticks, ran for cover as they came under fire in another Nairobi slum, Kibera. One person was shot and killed in Kibera overnight, said Sam Ochieng, a former chairman for Odinga's party there.
An Associated Press photographer said police used tear gas on a large convoy of vehicles carrying opposition officials that tried to enter Kibera. Police also fired guns into the air.
Most of the country of 45 million people remained calm the day after the election commission announced that Kenyatta, whose father was Kenya's first president after independence from British colonial rule, had won a second, five-year term.
In a victory speech, Kenyatta said he was extending a "hand of friendship" to the opposition, which alleged that the election commission's database had been hacked and results were manipulated against Odinga.
Kenyatta won with a decisive 54 percent of the vote to nearly 45 percent for Odinga, but the bitter dispute over the integrity of the election process tempered what many Kenyans had hoped would be a celebration of democracy in a regional power known for its economic promise and long-term stability.
The unrest also exposed divisions in a society where poverty and corruption at top levels of government have angered large numbers of Kenyans, including those who have been protesting in the slums and see Odinga as a voice for their grievances.
Adding to the rift is ethnic loyalty. Kenyatta is widely seen as the representative of the Kikuyu people, the country's largest ethnic group, while Odinga is associated with the Luo group, which has never produced a head of state.
But reconciliation efforts, the introduction of a progressive constitution in 2010 and an intense security operation during the recent election period have helped to ward off the kind of ethnic violence after the 2007 election in which more than 1,000 people were killed. Odinga ran unsuccessfully in that election; he also lost the 2013 vote to Kenyatta and took allegations of vote-tampering to Kenya's highest court, which rejected his case.
Recalling its failed legal challenge in 2013, the opposition has said it will not go to court again. Its top leaders have, so far, refrained from publicly calling for mass protests.
Catholic leaders on Saturday appealed for calm and asked security forces to exercise caution during protests.
"No life should be lost because of an election," said John Oballa Owaa, vice chairman of the Kenya Conference of Catholic Bishops.
In separate statements, Human Rights Watch and Amnesty International also called on police to exercise restraint.