The Palestinian Authority  must order an investigation into allegations of police brutality and the arbitrary arrest of demonstrators at a Ramallah protest on Sunday, Human Rights Watch said Tuesday."The police beat protesters and then arrested injured people, some even from the hospital," said Tom Porteous, deputy program director at Human Rights Watch . "The Palestinian Authority needs to make clear to the police that this is no way to handle a demonstration."Hundreds of protesters affiliated to the Popular Front for the Liberation of Palestine rallied in Ramallah on Sunday against the decision to return to peace talks with Israel.Clashes erupted after Palestinian police attacked the protesters as they marched toward the presidential compound. Injuries were reported on both sides."The demonstrators were trying to get past the barrier when the attack started," Khalida Jarrar, a PFLP member of the Palestinian parliament, told Human Rights Watch."I was talking to one of the policemen when I was shoved to the ground and they hit me hard while I was on the ground. When I got to the hospital [for treatment] some of the injured had been arrested and were in the police van. The police in the hospital were taking people’s IDs."Human Rights Watch said that the PA must conduct a "transparent and impartial investigation and publish its findings."The European Union Police Coordinating Office for Palestinian Police Support provides training to the Palestinian civil police forces."The Palestinian Authority and its foreign donors should not accept a police force that beats protesters without punishment," Porteous said.