PRISTINA, Kosovo (AP) -- Tensions were high in northern Kosovo on Sunday, with Serbs blocking roads after shots and explosions rang out overnight, Kosovo police and media reported. No injuries were reported.
The blocking of the roads with heavy vehicles and trucks took place a day after the Serbian president said he would ask the NATO-led peacekeeping force in Kosovo to permit the deployment of 1,000 Serb troops in the Serb-populated north of Kosovo, claiming they are being harassed there.
The road blocks, which Serbs say were erected to protest the recent arrest of a former Kosovo Serb police officer, came despite the postponement of the Dec. 18 municipal election that Kosovo Serbs were opposed to.
Serbia's president, Aleksandar Vucic, said Sunday that his message to the Serbs in Kosovo is that "there is no surrender and there will be no surrender." He claimed the Serbs had been forced to erect the road barricades to protect themselves from Kosovo security forces.
Kosovo Prime Minister Albin Kurti accused Belgrade of trying to destabilize Kosovo. He said Serbia also is trying to bring an end to the EU-mediated dialogue on normalizing bilateral ties and take it to the United Nations Security Council, where Belgrade hopes to get support from Russia and China.
Kurti called on Kosovo's Serbs "to distance themselves from the criminal groups and Vucic's regime that is funding them and looking for a war."
The European Union rule of law mission, known as EULEX, reported that a stun grenade was thrown at an EULEX reconnaissance patrol overnight. There were no injuries or damage.
EULEX, which has some 134 Polish, Italian and Lithuanian police officers deployed in the north, called on "those responsible to refrain from more provocative actions" and said it urged the Kosovo institutions "to bring the perpetrators to justice."
Unidentified masked men were seen on the Serb barricades that were blocking main roads leading to the border with Serbia, as Kosovo authorities closed two border crossings to all traffic and pedestrians.
On Sunday morning, the situation was calm on the barricades, but with an increased presence of Kosovar Albanian police in areas with a mixed population, and more international police and soldiers elsewhere.
Elsewhere, Serbian officials claimed that heavily armed Kosovo policemen "burst into" the premises of a strategic Serb-controlled dam on the artificial Gazivode Lake on the border with Serbia. The report could not be independently verified. The Serb officials asked for urgent EU action to "restrain the thugs" who, they alleged, want to trigger another war with Serbia.
Interior Minister Xhelal Zvecla, using the Albanian name for the lake, said that "situation at the Ujmani Lake is under control," adding that overnight there was an exchange of fire.
Serbia and Kosovo have intensified their war of words in recent days.
Vucic said on Saturday he would formally request permission from the NATO-led KFOR mission in Kosovo to deploy Serbian troops in the northern Kosovo, while conceding the request was unlikely to be granted.
Serbian officials claim a U.N. resolution that formally ended the country's bloody crackdown against majority Kosovo Albanian separatists in 1999 allows for some 1,000 Serb troops to return to Kosovo. NATO bombed Serbia to end the war and push its troops out of Kosovo, which declared independence in 2008.
The NATO-led peacekeepers who have been deployed in Kosovo since the1998-99 war would have to give a green light for Serb troops to go there, something that's highly unlikely because it would de-facto mean handing over security of Kosovo's Serb-populated northern regions to Serbian forces, a move that could dramatically increase tensions in the Balkans.
"We do not want a conflict. We want peace and progress but we shall respond to aggression with all our powers,' Kosovar Prime Minister Albin Kurti posted on social media.
Kurti told the European Union and the United States that they should "punish" Serbia for orchestrating the violence to "destabilize Kosovo."
Tension in the north has been high this week ahead of the polls initially planned for Dec. 18. They have now been postponed to April 23 in an attempt to defuse the situation.
The election was due after ethnic Serb representatives resigned their posts in November to protest a decision by Kosovo's government to ban Serbia-issued vehicle license plates.
Serb lawmakers, prosecutors and police officers also abandoned local government posts.
Tensions have been high in Kosovo ever since it proclaimed independence from Serbia, despite attempts by the EU and U.S. officials to defuse them. Serbia, supported by its allies Russia and China, has refused to recognize Kosovo's statehood.
Both Serbia and Kosovo want to join the EU but Brussels has warned they must resolve their dispute and normalize relations to be eligible for membership in the bloc.
NATO Secretary-General Jens Stoltenberg has said that the NATO-led mission in Kosovo "remains vigilant."