Kosovo election officials said they were weighing up whether to repeat a vote in Serb-populated areas that was violently disrupted by hardline extremists at the weekend. In a blow to Serbia, which hoped a peaceful election would further its EU ambitions, voting was interrupted late Sunday in the northern town of Kosovska Mitrovica after Serb extremists stormed a polling station and destroyed ballot boxes. "Only after we assess the electoral material, whether it is damaged or not, will we be able to see ... if the vote should be repeated," Valdete Daka, head of the central electoral commission, told reporters. The commission could decide to partially repeat the vote in the polling station affected or organise a re-run in the whole municipality of Kosovska Mitrovica, a source from the electoral commission told AFp The EU's foreign policy supremo Catherine Ashton said she would host a meeting on Wednesday with the leaders of Kosovo and Serbia to discuss the violence that marred the election. She "strongly" condemned the violence that took place, stressing that "all voters have the right to participate in elections in a safe and secure environment, free of violence." Ashton called for an investigation "without delay" into the violence. The head of the EU's election observer mission, Roberto Gualtieri, told reporters in Pristina that his team had logged "widespread ... intimidation and pressure against political activists and voters (that) was not conductive to a free campaign." The violence was "an attack on the fundamental right of the people to express their wishes through the ballot box," added Gualtieri. Sunday's vote was the first Serbia has backed since Kosovo unilaterally proclaimed independence from Belgrade in 2008. Some 120,000 ethnic Serbs live in Kosovo, whose 1.8 million population is mostly Albanian. Some 40,000 of them live in the north, where they make up the majority and enjoy control over some public institutions. The Organisation for Security and Cooperation in Europe (OSCE), which had a key role in organising the polls in northern Kosovo, said less than one in five Serb voters cast a ballot. Aside from the incidents in the north, the mission "evaluated the voting as good or satisfactory in the vast majority of observed polling stations," Gualtieri said. The Unites States, one of the first backers of an independent Kosovo, praised its "historic elections" while also condemning the attacks in Mitrovica. "We must not let the violence of a few overshadow the significant achievement this election represents," said US State Department deputy spokeswoman Marie Harf. "We applaud the commitment of both the governments of Kosovo and Serbia to encourage voter participation and enable the people of Kosovo to democratically choose their leaders," she added. The vote was seen as a test of an April deal brokered by Brussels to normalise ties between the former foes. That deal gave Serbia the green light to begin membership talks with Brussels. For Kosovo, a free and fair vote with a significant Serb turnout would be a positive step in its own push for closer EU ties. Kosovo's independence is recognised by most EU states.