The German government on Wednesday expressed alarm at the latest escalation of tensions between Belgrade and Pristina and said it was focusing on efforts to get Serb militants to dismantle barricades they have built near the Kosovo border.

Over the past three weeks, Serbs in northern Kosovo have set up more than 10 roadblocks in and around the city of Mitrovica partly in response to the arrest of a former Serb policeman accused of assaulting serving police officers.

The former Serb policeman, Dejan Pantic, has been released from jail and placed under house arrest, his lawyer Ljubomir Pantovic told AP news agency. Kosovo's Prime Minister Albin Kurti has criticized the court decision allowing Pantic to leave prison.

Kosovo shuts main border crossing with Serbia  

In addition, Serbs in Serbia on Tuesday erected another roadblock close to the Merdare crossing on Kosovo's eastern border in support of their ethnic kin, leading Kosovo to close its largest border crossing.

"The illegal barricades erected by Kosovo Serbs must be dismantled as quickly as possible," a spokesman for the German Foreign Ministry said.

He also said that "nationalist rhetoric in particular, such as we have heard from Serbia in recent weeks, is completely unacceptable."

The EU and US also jointly expressed concerns regarding "the continued tense situation in the north of Kosovo" and urged "everyone to exercise maximum restraint, to take immediate action to unconditionally deescalate the situation, and to refrain from provocations, threats, or intimidation."  

Former Munich Security Conference Chairman Wolfgang Ischinger blamed the Serbian government for igniting tensions and suggested that Belgrade is "playing with fire." 

What has been happening between Kosovo and Serbia?

Kosovo, a former Serbian province, has been a diplomatic sore spot in Europe for decades. It unilaterally declared its independence from Serbia in 2008 — a move that was illegal under Serbian constitutional law but is recognized by many other countries, including Germany.

The latest bout of tensions comes after representatives of the some 50,000 ethnic Serbs living in the north of Kosovo resigned from state institutions such as the police and judiciary following the Kosovo government's move to replace car license plates issued in Serbia.

The Kosovar Serbs refuse to recognize either the government in Pristina or Kosovo's independent status.

Military buildup in Serbia

The ongoing friction has prompted Serbia to put its troops on highest alert.

Serbian President Aleksandar Vucic has said he did so to "protect our people (in Kosovo) and preserve Serbia.''

He claimed that Pristina was preparing to attack Kosovo Serbs and remove the roadblocks by force.

Later on Wednesday, the head of Serbia's Office for Kosovo and Metohija Petar Petkovic said that Belgrade has "received guarantees from the United States and European Union that none of the Serbs in Kosovo who participated in protests and who took part in barricades will be prosecuted or arrested."

Pristina has asked NATO's mission in Kosovo, KFOR, to help dismantle the roadblocks, hinting that it might do so itself if NATO does not act. 

In turn, KFOR itself has called for dialogue between the parties involved.

"It is paramount that all involved avoid any rhetoric or actions that can cause tensions and escalate the situation," Major General Angelo Michele Ristuccia said in a statement.

"Solutions should be sought through dialogue," he added.

Any military intervention by Serbia in Kosovo would likely result in a clash with NATO forces and massively escalate tensions in the Balkans. The European region has yet to fully recover from the bloody breakup of Yugoslavia, which ended with NATO bombing Serbia and Montenegro in 1999. 

Russia denies involvement

Russia, a major Serbian ally, has meanwhile denied Kosovar accusations that it is fomenting tensions in the region, while confirming its backing for Belgrade.

"Serbia is a sovereign country and it is absolutely wrong to look for Russia's destructive influence here," Kremlin spokesman Dmitry Peskov said.

tj/dj (AP, Reuters, dpa)