(Adds EU call to step up Kosovo-Serbia border security, edits) By Ellie Tzortzi BELGRADE, March 10 (Reuters) - Serbia's coalition government, torn by division over the loss of Kosovo, was formally dissolved on Monday, opening the way for an early parliamentary election. The decision was taken at a brief cabinet session following Prime Minister Vojislav Kostunica's Saturday announcement that the government could not stay in office owing to disunity over the conflicting goals of defending Kosovo and joining the EU. "The government did not have a united and common policy any more," a statement said, "and this kept it from performing its basic constitutional function, to define and lead Serbia's politics." President Boris Tadic must now disband parliament and set a date for the election, probably on May 11. It will be the most important election since voters ended the era of the late autocrat Slobodan Milosevic in 2000. The vote will be a close race between the Democrats and the nationalist Radicals, the strongest party. Kostunica, whose party lies a distant third, quit after tacitly accusing his coalition partners, the Democrats and the G17 Plus party, of giving up on Kosovo, the 90-percent ethnic Albanian province which seceded last month with Western backing. Not all of the Union's 27 members have recognised Kosovo, but Brussels is deploying a supervisory mission that will monitor the territory's progress as an independent state. Tadic, also the head of the Democrats, said on Sunday that attempts to divide Serbs into patriots and traitors over Kosovo would backfire at the polls. A strong and stable Serbia would be in a better position to defend its interests, he added. "If we join the EU, then we can make sure that this outlaw state (Kosovo) never becomes an EU member," he said on a TV talk-show. Slovenian Foreign Minister Dimitrij Rupel, whose country holds the EU's rotating presidency, said he hoped for a victory for pro-European parties in the poll. "To be quite frank, I don't think there is any other possibility for our Serbian friends than the European Union. Where should they go?" he said in Brussels on Monday. NO CHANGE ON KOSOVO Serbia spent almost five months in limbo under a caretaker government in 2007, also under Kostunica, until he and the Democrats hammered out a policy they could both stand by. Their deep differences meant the government worked in fits and starts, between compromise and crisis, moving slowly on reforms and ending up last in the Balkan queue of EU hopefuls. Polls indicate the election could produce a hung parliament and a coalition deal might need long negotiations. Such a delay could stall urgent legislation and the arrest of war crime suspects -- a key condition for EU membership. But Kostunica's officials say the caretaker government will stay firm in its total opposition to independent Kosovo. "Serbs and other loyal citizens in Kosovo shouldn't worry," said Minister for Kosovo Slobodan Samardzic. Belgrade is instructing Kosovo's 120,000 remaining Serbs to sever ties with Kosovo's government and ignore a new EU mission. The Serb-dominated north is a flashpoint for any move towards a de facto partition. The EU urged the U.N. mission in Kosovo (UNMIK) to step up security along the border with Serbia amid fears of such a partition. EU diplomats said the bloc would call on Secretary-General Ban Ki-moon to ensure that the UNMIK police mission did not slacken in the run-up to an expected handover of duties to the EU-led police and judicial operation there from mid-June. Kosovo Prime Minister Hashim Thaci, who has warned Belgrade against trying to carve off part of the territory, said on Sunday Kosovo had contributed to Serbia's democratisation. "In 1999, when we pushed the police, army and administration out of Kosovo, Milosevic's fall from power started," he said at a border crossing where he unveiled a 'Welcome to Kosovo' sign. "Now, with Kosovo's independence, Kostunica has fallen, the mentality of the past has fallen in Serbia." (Editing by Andrew Roche)
Serb students march during a demonstration in the ethnically divided town of Mitrovica in Kosovo February 27, 2008. The United States is inciting instability in Europe by backing Kosovo's independence, Russia's ...