Serbia's president says the country is ready to send troops to Kosovo to protect Serbian nationals, if necessary.
The comment Sunday followed a war of words that erupted between Kosovo and Serbia officials when a train painted with the words "Kosovo is Serbia" was stopped Saturday from entering Kosovo.
The United States ambassador in Pristina Greg Delawie said on Twitter that he was concerned about the train issue. Delawie called “for restraint from all parties,” adding “Need normalization not confrontation” between Serbia and Kosovo
Serbian President Tomislav Nikolic said the two countries were on the verge of a conflict while Kosovo’s prime minister told journalists the train “sent a message of occupation.”
“I have asked them [police and interior minister] to stop imminently the train entering Kosovo at any price,” Kosovo President Hashim Thaci told Gazeta Express, an online news outlet.
But Serbia's Nikolic said Kosovo had shown it wanted war after it deployed special forces to prevent the train painted with Serbia's national colors from entering its territory.
According to reports, Serbia officials accused Kosovo authorities of attempting to mine the railroad with bombs.
Kosovo officials strongly denounced these accusations adding they found no explosives on the railway.
Saturday's ride was the first from Belgrade, the Serbian capital, to the northern Kosovo town of Mitrovica since the 1998 war. Reports say the train later returned to Belgrade.
About 120,000 of Kosovo's 1.8 million inhabitants are ethnic Serbs.
Both countries are seeking E.U. membership to boost their struggling economies.
Kosovo declared independence in 2008, a decade after it split from Serbia. The country has been recognized by the United States and more than 110 countries, but not Serbia.
The split triggered a bloody year-long conflict between Serbian and Albanian forces.
Many of the 40,000 ethnic Serbs living in northern Kosovo have refused to recognize the ethnic Albanian majority's 2008 secession from Serbia.