Serbs have begun voting in a snap general election widely seen as the most important since the overthrow of Slobodan Milosevic in 2000.

The vote could decide whether the Balkan country heads towards integration with the European Union or returns to isolation.

A pro-Western alliance led by President Boris Tadic is running neck and neck with ultra-nationalists.

Kosovo's declaration of independence has boosted the hardliners.

Disagreements over how to react when most EU countries recognised Kosovo led to the collapse of a fragile coalition between Mr Tadic's Democratic Party and Prime Minister Vojislav Kostunica's nationalist Democratic Party of Serbia.

Serbs in Kosovo are being allowed to vote in the election though the Kosovo Albanian government and UN authority say they believe the ballot there is illegal.

Some seven million Serbs are eligible to go to the polls which opened at 0700 (0500 GMT) and close at 2000 (1800 GMT).

Polarised nation

It is just over a year since the last, inconclusive general election.

A bitter campaign seems to have left them more polarised than ever, the BBC's Oana Lungescu reports from Belgrade.

Mr Tadic and his allies have hailed the signing of a long-delayed agreement with the EU as a signal that Serbia is on the road to membership of the prosperous bloc.

"The 11 May elections are a form of referendum at which citizens will decide on whether or not Serbia... will be a member of the EU," he said at the end of his campaign.

The ultra-nationalist Radical Party has argued that signing the EU agreement was tantamount to recognising Kosovo independence.

The party, whose leader Vojislav Seselj is currently on trial at The Hague international war crimes tribunal, has made clear it will not extradite any other suspects, and will seek closer ties to Moscow rather than Brussels.

One voter, Nina Aralica, told AFP news agency in Belgrade that the EU deal was the "only good sign for our future".

Another, Marko Vojinovic, said the deal "could only mean that we will become slaves to more developed countries".

Kosovo ballot

The results are too close to call and neither bloc is expected to win a decisive majority, our correspondent says.

Mr Kostunica, whose party has branded Mr Tadic a Judas and a traitor, could hold the key to any future coalition but so could the Socialists of the late dictator Slobodan Milosevic.

However, many fear that Serbia is headed once again for a weak government, if not months of political squabbling and instability, our correspondent adds.

In Kosovo, national and council elections have been organised directly by Serbia in defiance of the Albanian and international authorities.

Many Kosovo Serbs see the polls as a chance to elect genuine local leaders at last, the BBC's Nick Thorpe reports from Pristina.

Marko Jaksic, a Kosovo Serb leader in the ethnically divided town of Mitrovica, said he hoped the Radicals would win, describing Boris Tadic as the EU's "favourite puppet".

Oliver Ivanovic, a moderate Kosovo Serb leader in the town, suggested a win for pro-EU parties would benefit Serbs.

"If the democratic forces win these elections, I'm quit sure that Serbia will be very soon after in the EU," he said.

"And like a full member of EU, Serbia has much more possibility to protect its territorial integrity," he told the Associated Press.

BBC News