PRISTINA (Reuters) - Kosovo police blocked the entry on Saturday of a train from Serbia painted in the colors of the Serbian flag and with the words “Kosovo is Serbia” printed down the side, in a standoff seen as a test for the tiny Balkan country.

Kosovo President Hashim Thaci told an online paper he had ordered police special units to the border to halt the progress of the “provocative” train, which had not been cleared by the Pristina authorities to enter the country.

Serbia does not recognize the independence of Kosovo, its former province, and it did not seek any permission for the passage of the train, which it paid for and organized.

Kosovo media published video footage of police special units in armored vehicles rushing to the border with Serbia on Saturday.

“I have asked them (police and interior minister) to stop imminently the train entering Kosovo at any price,” Kosovo President Hashim Thaci told online newspaper Gazeta Express.

“Enough is enough,” Thaci said, adding that he was forced to take action after he saw the government was neglecting the issue.

Serbia retains effective control of the northern part of Kosovo, which is home to 40,000 to 50,000 Serbs who do not see Pristina as their capital. More than 90 percent of the population of Kosovo are of Albanian descent.

The two countries are in talks on normalizing ties, in a precondition for them both progressing toward membership of the European Union.

Belgrade’s formal rule of Kosovo ended in 1999 after NATO bombed Serbia for 11 weeks to compel it to withdraw forces who had killed some 10,000 Albanian civilians there. NATO still has some 5,000 troops stationed in Kosovo to keep the fragile peace.

Serbian Prime Minister Aleksandar Vucic said he had ordered the train to return to Belgrade from the border town of Raska, and he accused authorities in Pristina of attempting to ‎spark a conflict with the local Kosovo Serbs.

“Serbia wants peace... but this is my final plea and a clear warning to Albanians and a message to Serbs... do not attempt to use weapons against Serbs in Kosovo as Serbia will not allow that,” he told a news conference. He did not elaborate.

Serbian President Tomislav Nikolic has called for a meeting of the state Security Council on Sunday.

Vucic also said he will meet heads of intelligence agencies, commanders of military and police.

Saturday’s events come at a time of growing tension between the Balkan neighbors. Last week, French authorities arrested former Kosovo Prime Minister Ramush Haradinaj on a Belgrade arrest warrant accusing him of war crimes.

Haradinaj is considered a war hero by ethnic Albanians for his role as a guerrilla commander during the 1998-99 Kosovo war.