An American rights group is calling on the Palestinian Authority to investigate incidents where police beat protesters in the West Bank.

The New York-based Human Rights Watch said in two incidents, Palestinian police beat Palestinian demonstrators in the West Bank city of Ramallah in June and July. The group said six people were hospitalized.

The group said Palestinian officials conducted four inquiries but did not prosecute any of the police involved.

Palestinian security spokesman Adnan Damiri said Monday that some police were punished by their superiors but declined to say how many or how they were punished. He said none of the protesters filed complaints.

Activists charge that beatings and torture by Palestinian security agencies are common.