Boris Tadic (file photo)

Serbian Prime Minister Vojislav Kostunica has announced that he will not support reformist President Boris Tadic in Sunday's run-off presidential election.

Mr. Tadic is in a tight race with ultranationalist Radical Party candidate Tomislav Nikolic. The prime minister suggested that each citizen decide on his own how to vote.

Mr. Kostunica's announcement follows the president's rejection of his demands that Mr. Tadic commit himself to rejecting any accord on improved ties with the European Union, if an EU police and security mission is dispatched to Kosovo.

EU leaders agreed last month to dispatch the mission to replace United Nations administrators running the breakaway Serbian province, as its ethnic Albanian majority prepares to declare the area's independence.

Vojislav Kostunica (File)

Mr. Kostunica has insisted that dispatch of any mission requires U.N. Security Council approval.

Meanwhile, European Commission Vice President Franco Frattini met in Belgrade with top Serbian officials for talks on a plan to grant visa-free travel for Serbian citizens to the 27 EU member states.

The talks follow a decision by EU foreign ministers on Monday to offer Serbia an accord on opening trade and ending visa restrictions without signing a full agreement on building ties with that country.

Most EU ministers backed signing the full agreement, but the Netherlands blocked the effort because of Serbia's failure to fully cooperate with the U.N. tribunal on war crimes in the former Yugoslavia.

Some information for this report was provided by AFP and Reuters.