The United States on January 17 urged Serbia and Kosovo to avoid "dangerous rhetoric" as tensions between the two increase.
The latest incident occurred on January 14 after Belgrade sent a train with the words "Kosovo is Serbia" painted on the side toward a Serbian-dominated enclave in northern Kosovo.
The train was halted at the border after Kosovar authorities said they would intervene to stop it.
Belgrade, which doesn’t recognize the authority of the Kosovar government, said it halted the train because Kosovo’s security forces were planning to attack it.
Kosovo, supported by the U.S. and other Western states, declared independence from Serbia in 2008. Belgrade still considers it part of its territory. While 114 countries recognize Kosovo's independence, Serbia and Russia do not.
President Hashim Thaci of Kosovo has accused Belgrade of planning to seize a segment of northern Kosovo using the "Crimea model," a reference to Russia's annexation of the peninsula.
His Serbian counterpart, Tomislav Nikolic, has said Pristina showed it wanted war by deploying special police at the border to block the train.
The U.S. Embassy in Pristina, in its statement, said: "Kosovo is a sovereign, independent country, and we respect the right of Kosovo to manage who and what crosses its borders. We urge all sides to avoid dangerous rhetoric and continue to work for the normalization of relations."
Russian Foreign Minister Sergei Lavrov said on January 17 that the EU must act to help deescalate the situation in the Balkans. He said the tensions were being created "by the policies pursued by those who are imposing the so-called European values in a new, modernized post-Christian manner on all peoples in the Balkans."
Serbia’s Nikolic said that U.S. politics had caused "trouble" in the region and expressed hope the new Trump administration would be more supportive of Serbia's policies.
Kosovo's mostly Muslim ethnic Albanians make up 92 percent of its 1.8 million population. Northern Kosovo is home to about 50,000 Serbs, who do not accept Pristina's rule.