A human-rights group is bringing fresh allegations of torture by Kenya's security forces.  In a new report, Human Rights Watch says hundreds of civilians were tortured or beaten during a government security operation to disarm militants last year.

Human Rights Watch is calling for the Kenyan government to set up an independent investigation of an October military operation in the country's northeast.  According to the group, "scores" of men were tortured, at least a dozen women raped, and over 1,200 people wounded during the three-day operation to disarm militants.

Human Rights Watch says those found responsible for crimes should be punished.

The report is the latest of several recent accusations to hit Kenya's police and military.  Earlier this year, a U.N. investigator on extrajudicial killings recommended the dismissal of Kenya's police chief and attorney general for failing to rein in the widespread use of extrajudicial killings and other misconduct by security forces.

Kenyan and international rights groups charge police carried out illegal killings during an operation that targeted the Mungiki criminal gang and fired on protesters following disputed 2007 elections.

Human Rights Watch director Kenneth Roth said the trend is troubling.

"This is not anywhere near the first time that abusive security forces have engaged in this kind of misconduct," Roth said.  "Increasingly it appears to us that the security forces have become a law unto themselves.  That they stand above the rule of law that supposedly governs here in Kenya."

Kenya's police have rejected the accusations of Human Rights Watch and Kenyan security officials have also dismissed previous accusations of wrongdoing, criticizing the accuracy and motives of human-rights investigators.  The response of politicians in Kenya's grand coalition government has been more divided.

Members of president Mwai Kibaki's Party of National Unity have tended to dismiss the claims, while many in Prime Minister Raila Odinga's Orange Democratic Movement have said the charges should be followed up.

The operation described in the report was launched after clashes between clans near Mandera left more than 20 people dead.  Such violence is common in the area, near the borders with Somalia and Ethiopia.

According to interviews conducted in the area by Human Rights Watch, security forces would round up all of the men in a town and beat them in an effort to locate militia members and weapons.  Witnesses said the beatings were carried out with canes or iron rods and that some men's testicles were crushed or ripped open.  Widespread looting was also reported. 

Roth says official misconduct cannot be dismissed as the work of a few bad apples.

"This was clearly an operation directed from above.  And the torture that we described in this report was systematic and widespread, so much so that we believe there is a good case to be made that crimes against humanity were committed," said Roth.

According to Human Rights Watch, the security operation may not even have been particularly effective.  The group says many of the weapons handed over by the community, in an effort to end the crackdown, were purchased from arms dealers across the border in Somalia, rather than recovered from militia members.