The Serbian government's decision on Friday to open a new train line connecting the capital Belgrade and the city of Mitrovica in northern Kosovo sparked anger by Kosovo's government, which decided to block the line at the border. Mitrovica has a large population of ethnic Serbs. The two countries have been locked in a territorial conflict for years, as Serbia has never recognized the sovereignty of its southern neighbor that declared its independence from Serbia in 2008. The train that was halted at the border was decorated with Serbian flags and slogans in 20 languages saying "Kosovo is Serbian". DEBKAfile's diplomatic sources report that the timing of the incident was not a coincidence, but rather directly tied to Friday's inauguration of US President-elect Donald Trump. Serbia is backed by Russia while Kosovo is supported by Western European countries and indirectly by the Obama administration. A full analysis of the expected developments between Serbia and Kosovo and their effect on the relationship between the superpowers will be covered in Friday's issue of DEBKA Weekly.