NAIROBI, Kenya -- In an escalation of Kenya's deadly election violence, police on Saturday fired live ammunition at rioters and used tear gas on vehicles carrying opposition officials trying to enter a Nairobi slum where they have strong support. A young girl was killed by a stray bullet, nine bodies with gunshot wounds were brought overnight to the capital's main morgue, and a watchdog group said police gunfire has killed 24 people since Tuesday's disputed vote.

The chaos in the Nairobi slums of Mathare and Kibera, as well as in the opposition stronghold of Kisumu city, contrasted with widespread calm - and celebrations in some areas - in the country of 45 million after Kenya's election commission said late Friday that President Uhuru Kenyatta won a second term. Protests, often violent, began soon after voting when Kenyatta's main challenger, Raila Odinga, alleged vote-rigging.

The government said life was returning to normal and that those challenging security forces were criminals intent on looting and destroying property. However, the police came under scrutiny for what the Kenya National Commission on Human Rights, which monitors government institutions, described as the "unlawful and unacceptable" use of excessive force.

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Seventeen of the two dozen people shot by police died in Nairobi, the commission said. It cited allegations of police breaking into homes, beating people, threatening them with rape and demanding money. The watchdog group also lamented "the destruction of private property by both civilians and allegedly by security personnel in the course of their duty."

Kenyan policemen walk during clashes with supporters of opposition leader Raila Odinga, in Kibera slum, in Nairobi, Kenya August 12, 2017. Goran Tomasevic / Reuters

Police shot and killed two people during riots by opposition supporters on the outskirts of Kisumu, a regional police commander, Leonard Katana, said Saturday. Another five people were injured by gunfire in Kisumu, Katana said.

In Mathare, where Odinga has significant support, 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.

One Mathare resident, Wycliff Mokaya, told The Associated Press that his 9-year-old daughter was killed by a stray bullet while on the third-floor balcony of their home.

"I was watching her play with her friends when she suddenly fell down," Mokaya said. "She was my only hope."

Nine bodies with gunshot wounds were brought to the Nairobi morgue from Mathare, a mortuary official said Saturday. The official spoke on condition of anonymity because he is not authorized to speak to the media.

An Associated Press photographer said police used tear gas on a large opposition convoy trying to enter the Kibera slum. Police also fired shots in the air.

A woman cries as she stand behind policemen during clashes between supporter of opposition leader Raila Odinga and policemen in Kibera slum in Nairobi, Kenya, August 12, 2017. Goran Tomasevic / Reuters

The Kenya Red Cross said it helped a total of 93 people who were injured during the clashes since the election results were announced.

Police harassed and assaulted at least four journalists covering the violence, witnesses said.

The unrest followed a victory speech Friday in which Kenyatta, whose father was Kenya's first president after independence from British colonial rule, said he was extending a "hand of friendship" to the opposition.

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 opposition said the election commission's database had been hacked and results were manipulated against Odinga.

The unrest also exposed divisions in a society where poverty and government corruption 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 and the introduction of a progressive constitution in 2010 have helped to defuse fears of the kind of ethnic-fueled violence that followed 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. It has not directly urged supporters to stage protests, instead telling them to stay safe.