For two terrifying hours, the woman crouched inside her shop, watching as a gang attacked five men in the street, pulled down their trousers and sliced their genitals with rusty machetes.
"The men were screaming and saying, 'Please don't kill me, don't cut me,"' the 35-year-old vendor told The Associated Press, asking to be identified only by one initial, K., because she feared reprisals by the gang.
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In the violence that has followed Kenya's disputed presidential election, a notorious gang has been mutilating the genitals of both men and women in the name of circumcision — inflicting a brutal punishment on members of a rival tribe that does not traditionally circumcise.
The attacks do not appear to be widespread, but they drive home how a fight touched off by opposition allegations that Kenya's president stole the election has exploded into a broader conflict fueled by ethnic resentments in what had been one of Africa's most stable nations.
Many of the mutilation victims belong to the Luo tribe of opposition presidential candidate Raila Odinga, say witnesses and even a recruiter for the gang itself.
The gang, called the Mungiki, draws mostly from President Mwai Kibaki's Kikuyu tribe, which has long dominated politics and business in this East African country.
Mungiki, which means "multitude" in Kikuyu, originally promoted traditional Kikuyu practices, including female genital mutilation. But in recent years it has become involved in extortion and murder and it also provides hired muscle for politicians.
The recruiter called forced "circumcisions" simple revenge on Luos for attacks on Kikuyus since the Dec. 27 election. More than 600 people have been reported killed in the upheaval.
"They must pay for the destruction and the deaths," the female recruiter said, speaking on condition of anonymity because the gang has been outlawed since 2002, after its members beheaded 21 people in a turf war with a rival gang.
Circumcision is a rite of passage for male members of the Kikuyu and most other Kenyan tribes, but the Luos do not practice it.
Millie Odhiambo-Mabona, a lawyer with a children's rights group who reported hearing of numerous such attacks, said mutilation is a "weapon of war" for groups that practice traditional circumcision.
"Because for the communities that don't practice circumcision, if you forcefully circumcise them, then it's meant to be degrading," she said from Nairobi in a telephone interview with the AP in New York.
The number of mutilations appears to be relatively small, measured against the violence that has wracked Kenya.
K., interviewed in the Nairobi slum of Kibera, reported seeing five men harmed in this way, including at least two whose penises were cut off and thrown into a fire. She said she believed those men died because she saw the attackers throw the bodies behind some kiosks.
The Mungiki recruiter confirmed three other "forced circumcisions."
A surgeon at Kenyatta National Hospital, the main government hospital in the capital, said he had operated on two men with injuries to their penises, at least one of whom was a Luo.
"There were cuts around the foreskin, probably an attempt at circumcision," the doctor said, speaking on condition of anonymity.
A mortuary assistant in Nairobi said out of 78 bodies brought to his facility since the fighting started, two adult males appeared to have been crudely circumcised before being hacked to death. The assistant insisted on speaking anonymously out of fear of reprisals.
"We have received some reports of what's happening to predominantly Luo men who are not believed to be circumcised," said Muthoni Wanyeki of the Kenyan Human Rights Commission. "These attacks are happening in areas that Mungiki is active."
K., the vendor, said she recognized the attackers outside her shop as Mungiki. She said that over a two hour period, she watched the gang waylay five men; each attack took about five minutes.
"My husband also was hiding at the shop with me," she said. "My husband was afraid they were going to attack him next so we stayed quiet, quiet."
Since witnessing the mutilations, K. has abandoned her business selling vegetables and chickens in a predominantly Kikuyu area of Kibera.
"I will never go back there," she said. "I hear it's still going on."
John Holmes, the United Nations undersecretary-general for humanitarian affairs, said he had received reports of genital mutilation.
He said the United Nations calls on "all leaders to stop this kind of violence, to nip this kind of ethnic fighting and singling out people for attacks on the basis of ethnicity in the bud before it becomes any worse."
Dr. Samwel Oyugi, a Kenyan who practices geriatric and internal medicine in New York but has been visiting his homeland during and after the election, said several people had told him about genital mutilations.
"What they say they saw were some of their relatives that were forcefully circumcised, and some that were killed," Oyugi said in a telephone interview with AP in New York. "Basically, you're held down by a group of people from the Kikuyu tribe, and they basically cut your foreskin, without any regards to how much pain they cause."
Edward Omolo, a Kenyan who teaches biology at Central Pennsylvania's Community College, said he had heard of about 20 mutilation killings, including his 45-year-old Luo uncle who bled to death after suffering forced "circumcision" in a Nairobi slum around Dec. 30.
"He was killed, circumcised to death," said Omolo, who spoke with the AP during two interviews, one in person outside U.N. headquarters in New York, the other by phone from his office.
Omolo, who also said a niece and her 7-month-old daughter had been hacked to death by matchetes in another attack, blames Kibaki for the bloodshed. He drove last week from Harrisburg to New York to join about 50 protesters demanding a new government for Kenya.
"The only way is to get a legitimate government, and let that government sort out the problems," he said.