Police say assailants in western Kosovo have launched a rocket-propelled grenade at the barracks of the country's new security force. NATO-led peacekeepers have sealed off the area in the town of Pec after the attack late Thursday. The blast damaged the building, but no one was injured. The attack comes a day after the Kosovo Security Force replaced a 3,000-strong civilian emergency organization formed out of the disbanded ethnic Albanian guerrilla force. It was unclear who was behind the attack. Serbia protested the creation of the force saying it was designed to intimidate the Serb minority in Kosovo. Earlier on Thursday several dozen ethnic Albanian former guerrilla fighters protested at being left out of the new force.