A general election is likely to be announced in Serbia this week after the Government collapsed in the wake of Kosovo's declaration of independence.

Boris Tadic, the pro-Western President, is expected to confirm that a poll will be held in May after Vojislav Kostunica, the Prime Minister, declared that his party would withdraw from government in protest at its continued commitment to joining the European Union.

The vote will be seen as a referendum on the country's future direction, either towards Brussels or into Russian-backed isolationism, just as Mr Tadic's victory in presidential elections last month was interpreted as a sign that Serbia would face West.

The increasingly nationalistic Mr Kostunica, who agreed to form a Government with Mr Tadic only last May, has denounced the EU after 18 of its 27 members recognised the breakaway Serbian province of Kosovo when it declared independence last month.

One of the election's key flashpoints is likely to be the fate of about 100,000 Serbs in the newly independent Kosovo who will find themselves disenfranchised.

Dragan Sutanovac, the Defence Minister and vice-president of Mr Tadic's Democratic Party, said: “The vote will be a referendum on Serbia's European perspective - or on its isolation.”

Serbian voters “have already delivered their judgment in the presidential elections, but it is obvious that some politicians did not understand what the Serbian citizens want”, he said.

Mr Kostunica has insisted that Serbia should resume talks on joining the EU only if European countries repudiate their “illegal” recognition of Kosovo, a policy that would effectively rule out membership.

He has pledged to convene the Cabinet tomorrow to propose a dissolution of Parliament and national elections for May 11, when local elections were already due to be held.

“The Government of Serbia has no united policy any more on an important issue related to the future of the country - Kosovo as a part of Serbia,” Mr Kostunica said. “Such a government could not function any more.”

Mr Tadic has sought to keep the issues to EU membership and Kosovo's status separate. In a statement, he said: “I respect the Prime Minister's decision that he is no longer able to lead the Government of Serbia and, when I get the Government's decision, I will call an election.

“Elections are the democratic way to overcome political crises and the people are the only ones who have the right to decide which is the way forward for Serbia.”

The uneasy Cabinet alliance of Mr Kostunica's conservative Democratic Party of Serbia and Mr Tadic's Democrats was formed after strained negotiations after elections four months earlier. Mr Kostunica could now form an alliance with the nationalist Radicals, the biggest party in Parliament, whose candidate narrowly lost the presidential poll to Mr Tadic.

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