Human Rights Watch says "widespread sexual violence against women and girls, and sexual attacks on men" were committed by men in uniform during the Kenyan election.
Kenyan security forces raped, beat and assaulted civilians during violence in recent elections, Human Rights Watch said on Thursday.
"There was widespread sexual violence against women and girls, and sexual attacks on men," HRW said, in a report titled, "They were men in uniform."
The violence, documented during Kenya's election in August by HRW and other rights groups, recorded "police use of excessive force against protesters, killings, beatings and maiming of individuals, looting and destruction of property."
The report was based on interviews with 65 women, three girls and three men who were sexually attacked.
About half of the rapes reported to HRW were gang rapes.
"About half of the women interviewed said that they were raped by policemen or men in uniform," the report read, adding that many attacks were also accompanied by torture and violence against the women's children and husbands.
At least 58 people have died during violent clashes since the August vote, which split the country along ethnic and regional lines.
The August 8 poll was annulled in September by the Supreme Court, citing "irregularities and illegalities."
The court ordered a re-run in October that was boycotted by the opposition, handing President Uhuru Kenyatta a landslide of 98 percent of votes cast by just 39 percent of the electorate.
A government civilian watchdog tasked to oversee the police exists, but few officers are charged and convictions are extremely rare.
The sexual violence mirrored widespread violations against women after a disputed 2007 vote, when 1,200 people were killed, HRW said.
At the time, the group documented at least 900 cases of sexual violence but said this was likely an underestimate.
"The new cases related to the August and October 2017 elections demonstrate a disturbing continuum," Tina Alai, a lawyer with New York-based Physicians for Human Rights.
"Police have continued to perpetrate sexual violence against civilians they are obligated to protect," she said.