The EU justice mission on Friday charged 15 former Kosovo rebel fighters for alleged war crimes including murder and torture committed during the 1998-1999 war with Serbian forces.

The identities of the defendants were not revealed, but local media reported that they include former KLA commander Sylejman Selimi, who is now Kosovo's ambassador to Albania, and Sami Lushtaku, mayor of northern town Srbica and a top official in Prime Minister Hashim Thaci's ruling party.

The premiers of Kosovo and Serbia, Hashim Thaci and Ivica Dacic, vowed Wednesday to keep a peace deal on track despite election violence by Serb extremists in Kosovo.

"Both governments condemned the incidents," Thaci said as election officials in Kosovo ordered a re-run vote in a town where Serbs stormed a polling station and destroyed ballot boxes on Sunday.

Kosovo election officials said Wednesday they had decided to annul a vote in a Serb-populated town that was violently disrupted by hardliners last weekend, and ordered a re-run.

The central electoral commission said results from three polling stations in Serb-populated Kosovska Mitrovica were "annulled due to damaged ballot boxes".

Serbia's war crimes prosecutor on Wednesday charged two army officers with the murder of at least 27 Kosovan civilians including a young child during the 1998-1999 war.

Pavle Gavrilovic and Rajko Kozlina are charged with committing a war crime against civilians in March 1999 in the southern Kosovo village of Trnje, the prosecutor said in a statement.

NATO head Anders Fogh Rasmussen on Monday "strongly condemned" the violence that marred key weekend polls in Kosovo and said the military alliance was committed to maintaining its presence there.

Rasmussen said NATO troops in Kosovo stepped in at the request of the European Union on Sunday, when Serb extremists stormed a polling station in Kosovska Mitrovica, the main Serb-populated town in the ethnically divided territory.

Violence and low turnout in Kosovo elections underscored the deep divisions in the territory and dealt a blow to Belgrade, which had sought to further its EU membership bid by urging ethnic Serbs to vote peacefully.

The weekend vote, the first Belgrade has backed since ethnic-Albanian majority Kosovo proclaimed independence in 2008, was seen as a test of an April deal brokered by Brussels to normalize ties between the former foes.

Polls opened Sunday in key local elections in Kosovo that are being closely watched by the European Union amid fears of a boycott by minority Serbs, voting for the first time since independence in 2008.

The election of deputies and mayors in 36 Kosovo municipalities is seen as a key test of relations between Pristina and Serbia after an historic EU-brokered deal to improve ties.

Important elections Sunday in Kosovo will be watched for the turnout of its minority Serb population and as a vital step in Serbia's bid to join the European Union.

Kosovo, the territory which sparked a war between Serb forces and ethnic Albanian rebels in 1998-1999, remains the main stumbling block in Serbia's membership process.

The European Union urged voters across Kosovo on Thursday, including Kosovo Serbs, to participate in key weekend local elections as it announced extra funding to cushion a Serbia-Kosovo peace deal.

"The November 3 elections are a key moment in Kosovo's future and are an important element in the implementation of the April Agreement and the process of normalization of relations between Kosovo and Serbia," EU foreign policy chief Catherine Ashton said in a statement.

The parents of a Roma schoolgirl whose deportation from France sparked a furor and rocked the government have again applied for French residency, their lawyer said.

Leonarda Dibrani, 15, was deported to Kosovo earlier this month along with her parents and siblings. Her case triggered outrage as she was taken by the authorities while she was on a school trip.