Kostunica's government formally stepped down on Monday, March 10, and called for early elections in May after its coalition parties fell out over the issue of how to deal with the European Union following the support of many EU states for Kosovo's secession.
European Union officials said they hoped the coming polls would benefit pro-European parties.
"With the coming elections, we hope that the European forces will win," said Slovenian Foreign Minister Dimitrij Rupel, whose country holds the EU's rotating presidency.
EU foreign ministers meeting in Brussels were unanimous in calling on the people of Serbia not to turn their backs on Europe by supporting Serbia's nationalistic parties in the election.
"Europe needs Serbia and Serbia needs Europe," Sweden's Foreign Minister Carl Bildt said.
"Were Serbia to sink into self-isolation, it would clearly be to the detriment of the economy (and) politics ... of Serbia, but also of the entire region."
Kostunica opposes EU support of Kosovo
EU officials, who supported the re-election of Serbian President Boris Tadic last month, were concerned last week after Serbian nationalists, including Kostunica, called for a parliamentary vote to stop Serbia's further integration into the EU.
The resolution, which was ultimately turned down on Thursday, crafted in response to many EU member states' support for Kosovo's declaration of independence, also condemned the EU's deployment of a peace and justice mission to help supervise the new state's institutions.
As a result, Kostunica resigned Saturday, opening the door for new elections, expected to take place on May 11. Bildt, who recently returned from a visit to Kosovo, said he sees the vote as "an opportunity to choose the European course more firmly than they have done before."
Proposals for EU incentives
"What we have to do is to show the Serbian population that we want them in the European Union," said External Relations Commissioner Benita Ferrero-Waldner.
To do this, the commission offered several proposals last week for building a stronger relationship with Serbia. Incentives include easier visa procedures, a doubling of scholarships and better EU-Serbia transport links.
The EU already has initialed, though not signed, a Stabilization and Association Agreement with Belgrade, the first step on the long road to membership in the bloc. Pro-Western President Tadic has insisted that despite disagreements over Kosovo, Belgrade has no alternative but to join the bloc as soon as possible.