BRUSSELS, July 18 (Reuters) - Serbia said on Tuesday it had yet to decide whether to take part in talks next week on the future status of Kosovo, adding that independence for the province would cause instability in the Balkans and beyond.
Serbian President Boris Tadic said Belgrade was waiting for U.N. mediator Martti Ahtisaari to outline details of the talks which are planned for July 24 in Vienna.
"After that we are going to decide. We are ready to participate, but we need some conditions on those talks," Tadic told a news briefing during a visit to Brussels.
"An independent Kosovo ... is going to be a problem for regional stability, not only for the Balkans but for other regions in the world," he added.
This highest-level meeting between the two sides since NATO drove out Serb forces from the province in 1999 would be the first to address Kosovo's final international status -- independence or autonomy -- since talks began in February.
Kosovo said on Monday it would demand independence from Serbia during the talks. Ninety percent of Kosovo's 2 million people are ethnic Albanians impatient for independence.
Serbia has offered wide autonomy for land it sees as the sacred cradle of the nation.
Serb negotiators want to see an agenda for the talks and an agreement on their format and structure before deciding whether Tadic and Prime Minister Vojislav Kostunica would attend.
Tadic said Serbia sought a compromise "appreciating the legitimate interest of the Albanian nation in Kosovo" while defending Serbia's "territorial integrity and sovereignty".
Belgrade daily Blic said Kostunica was having second thoughts about talks with Kosovo Prime Minister Agim Ceku, whom Serbia accuses of war crimes.
A no-show by Belgrade would be frowned on by Western powers, which want a deal within the year, concerned that a delay could spark fresh violence against the U.N. mission and Kosovo's 100,000 ghettoised Serbs.
U.N. Secretary-General Kofi Annan said U.N. mediator Ahtisaari had not set out to impose a solution on Kosovo.
"I would wait for the outcome of his work and then we'll make a judgment on how to proceed," he told a news conference in Brussels.
Diplomats say Kosovo is heading for independence under EU supervision and secured by a NATO peace force, adding that if an agreement cannot be reached, the U.N. Security Council will have to make a decision on Kosovo's status. (Additional reporting by Matt Robinson in Pristina)