(ANSA-AFP) - BELGRADE, MAY 26 - Police used tear gas on Friday to disperse Serbs who gathered in front of municipal buildings in northern Kosovo, after police helped install ethnic Albanian mayors following controversial elections. Serbian residents -- who rallied at the sound of an alarm commonly used in response to the presence of Kosovo police -- clashed with the officers in the Serb-majority town of Zvecan, AFP journalist saw. They were eventually pushed back. In various videos posted online, gunshots and shock bombs could also be heard. Ambulances arrived to the scene but it was not immediately clear if there were injuries. Kosovo police did not comment on the incidents, but only confirmed that officers were assisting newly elected mayors to enter the premises. "According to their official duty, today the Kosovo Police is assisting the mayors... to exercise their right to work, in the official facilities of the respective municipalities," the Kosovo Police said in a statement. (ANSA-AFP).