PRAGUE, Dec 15 (Reuters) - Kosovo's Prime Minister Albin Kurti submitted a bid for Kosovo to join the European Union on Thursday, launching a process that could take years, if not decades, and is dependent on it normalising relations with neighbouring Serbia.We want to build the EU in our country with our people," Kurti said after handing the application to Czech European Affairs Minister Mikulas Bek.While there is reluctance within the 27-nation EU for further expansion, Russia's invasion of Ukraine has led them to devote more energy to improving relations with the six Balkan countries of Albania, Bosnia and Herzegovina, Kosovo, Montenegro, North Macedonia and Serbia."We firmly believe that a European future is the only way to solve a number of problems in the region, whether economic, social or ethnic," Bek said.EU and U.S. envoys this week called on Kosovo and Serbia to remain calm amid an ongoing ethnic crisis in the north of Kosovo where local Serbs have erected barricades to prevent police movement, part of tensions between authorities and Kosovo's Serb minority."