Brussels watches as Serbs head to polls

The difference in positions between the candidates is quite stark: Mr Nikolic favours closer ties with Russia, while Mr Tadic sees EU integration as the only way forward for Serbia.

The latest polls put Mr Tadic slightly ahead of his opponent, with 2.1 to 2.35 million people saying they would vote for him, while 2 to 2.25 million voters said they would instead put their trust in Mr Nikolic, Serbian news site B92.net reports.

During the first round of the elections on 20 January, Mr Nikolic obtained almost 40 percent of the votes, coming ahead of Mr Tadic, who won 35 percent.

The redistribution of votes for the three other candidates who obtained more than five percent in the first round is therefore crucial.

However, it remains unclear to whom the votes of the New Serbia candidate Velimir Ilic - backed by Prime Minister Vojislav Kostunica, will go. Mr Ilic got 7.6 percent in the first round.

Premier refuses support to either of the candidates

Mr Kostunica said on Wednesday (30 January) that he would not support Mr Tadic's bid, after he refused to agree that all pre-accession documents signed with the EU would become void should the bloc recognise the independence of Serbia's breakaway province of Kosovo.

The prime minister said he would therefore not back either of the candidates.

"Our message is the people should choose on their own what to do on 3 February," he was quoted as saying by Reuters.

"My attitude towards the election is based on the fate of Kosovo. The elections have been marked by the question of whether we'll preserve Kosovo," he added.

The fate of Kosovo – the Serbian province governed by the UN since 1999 – has been a central element of the pre-electoral campaign.

Both candidates oppose the province's independence, but according to analysts, Mr Tadic would not bring a halt to the EU integration process even if the bloc recognised Kosovo, while Mr Nikolic would do so.

EU has its preferences

Wanting to see the pro-European Mr Tadic re-elected, the EU has been looking for ways to give a subtle boost to the candidate.

This week it decided to propose to Serbia an interim political agreement to be signed on 7 February, offering closer trade relations, relaxed visa requirements and educational cooperation.

The bloc denied the move was an attempt to interfere in the country's elections.

"We are of course on the side of those who want an EU future for Serbia," Slovenian foreign minister Dimitrij Rupel, whose country currently holds the rotating EU presidency, told MEPs on Tuesday (29 January).

But he added: "Even if each of us has personal preferences, these did not play a role" in the decision to offer the political agreement to Serbia.

In any case, the EU move is expected to have little effect on Serbian voters "because Tadic voters are pro-European anyway, and Nikolic voters are not even thinking about this," analyst Aleksandar Vasovic told Reuters.

In addition, it has provoked frustrated and bitter reactions in the neighbouring Balkan countries, who would all like to move forward with their European integration.

Bosnian and Macedonian media this week criticised the bloc's "double standards", saying they could be detrimental to the reform processes in the other Balkan countries.