Serbian Prime Minister Aleksandar Vucic says he has decided to stop a train from traveling from Belgrade to Serb-dominated northern Kosovo.
Serbia launched the promotional railway service on January 14, despite protests from the government in Pristina.
The promotional ride would have been the first from the Serbian capital to the town of Mitrovica in Kosovo since the 1998-99 war.
Vucic announced his decision to stop the train at a press conference in Raska, a city in southern Serbia bordering Kosovo.
"[Kosovo's] special units mined the railway and other special units were sent to the border to arrest the train driver and the passengers," he said.
Kosovo's Prime Minister Isa Mustafa welcomed the decision, saying the train would not have been allowed into his country.
"We mobilized all state mechanisms to deal with this situation," Mustafa said.
Kosovo's Interior Minister Skender Hyseni earlier said authorities had been ordered to block the train, which had already reached Raska.
The train, which Serbia bought from Russia, is painted in the colors of the Serbian flag and features pictures of churches, monasteries, and medieval towns, as well as the words "Kosovo is Serbian" in 21 languages.
Its journey was expected to take 10 hours on the long-established railway tracks with several stops along the way.
Serbia has said the train ride could turn into a regular service after a trial period from January 20 to February 26.
The developments come amid already heightened tensions between Belgrade and Pristina after the recent detention in France of a former Kosovar prime minister on an arrest warrant from Serbia.
Ramush Haradinaj was detained on January 4, but a French appeals court released him this week and ordered him to remain in the country while it reviews Serbia's extradition request.
Belgrade wants to try Haradinaj for offenses related to the 1998-99 war in its former province.
Serbian Justice Minister Nela Kuburovic warned that Belgrade would hit back if France does not grant its request.
Kosovo State Minister Edita Tahiri on January 13 accused Serbia of threatening regional stability and urged the European Union to intervene.
Serbia and Kosovo, a former province which unilaterally declared independence from Belgrade in 2008, have been locked in EU-facilitated talks since 2011 to normalize ties.