Kenya's police have denied claims of torture and rape when they disarmed rival clan militias last year. Human Rights Watch says there should be an inquiry into the "collective punishment" of civilians in Mandera. The US-based organisation said its research showed thousands of people had been tortured and women had been raped. But police spokesman Eric Kiraithe told the BBC there had been no torture or beatings and asked HRW to produce evidence to back up its findings. "Certainly we should look into the laws in this country which allow any street boy to come here and publish very disparaging lies about our internal security forces," he told the BBC's Network Africa programme. Earlier this year a UN investigator into allegations of extrajudicial killings elsewhere in Kenya, Philip Alston, said the police were a "law unto themselves". 'Not a case of bad apples' According to Human Rights Watch, a joint police and military operation to disarm the warring militias in the north-eastern town of Mandera took place between 25 October and 28 October 2008. It followed deadly clashes between the local Garre and Murulle clans, which had killed 21 people earlier in the year. "Unfortunately, that joint operation pursued a brutal strategy of basically rounding up all of the civilians in various villages and then, in a sense, collectively punishing them," the report's author Ben Rawlence told the BBC. "Requiring them to turn over weapons, to disclose the whereabouts of the militias who've been fighting, torturing thousands of people and raping some women… destroying property and causing between 20,000 and 30,000 people to flee the area." In February, Human Rights Watch researchers visited five of the towns and say they documented consistent accounts from more than 90 victims. The interviewees said security forces entered early in the morning and rounded up all of the men they could find. They were made to lie on the ground for hours and were beaten with rifle butts, sticks, canes and iron rods. "In front of the police station, they made us lie down. They were beating us with sticks, rungus [clubs], anything. They weren't saying anything except beating us and then: 'Bring the gun or you'll die,'" a victim in El Wak said. Other said the security forces twisted, crushed or ripped open their testicles. "This is not a question of a few bad apples disobeying orders," Kenneth Roth, Human Rights Watch's executive director said. "This operation was the result of a strategy devised by senior officials to use brutal force against Kenyan citizens." Mr Kiraithe has denied previous accusations of police brutality and said if Human Rights Watch had evidence of torture in the Mandera district, the organisation should hand it over. "We have well over five institutions in this country prepared to carry out public prosecutions and ensure that justice is done," Mr Kiraithe said. The region around Mandera is prone to conflicts between rival clans, often for control of scarce water and pastures. The area is largely inhabited by Somali-speaking nomads. Source: BBC