Updated

An international human rights group said Friday that Kenyan security forces abused ethnic Somalis in Kenya's border region in response to attacks by militants from Somalia and have never been punished for the abuses.

Human Rights Watch said in its Friday report that a woman was raped by a police officer at the world's largest refugee camp during a raid by Kenyan police in December. The group said other refugees were beaten, robbed and extorted.

Kenya Police Commissioner Mathew Iteere said Friday that the police would investigate the accusations in the report.

Kenyan police blame sympathizers of al-Qaida-linked al-Shabab militants from neighboring Somalia for the killing of at least 30 Kenyans in separate attacks. The militants have vowed to carry out a large-scale attack on Kenya for sending its troops into Somalia in October.

Human Rights Watch said that police targeted ethnic Somalis for abuse after grenade and improvised explosive device explosions in Kenya.

"The attacks carried out by suspected al-Shabab supporters are abhorrent, but they can never justify this kind of indiscriminate abuse," said Leslie Lefkow, deputy Africa director at Human Rights Watch. "Kenyan police and soldiers ought to be protecting civilians, not assaulting them."

The group said that the abuses by security forces documented through interviews with 55 victims included rape, attempted sexual assault, arbitrary detention, extortion, destruction of property, and various forms of physical mistreatment.