PRISTINA, Serbia -Kosovo separatists enraged Serbia by declaring independence in February, and it has driven many Serbs to support ultranationalists in Sunday's parliamentary elections.

Now, Kosovo's ethnic Albanian majority and its Serbian minority alike fear the fledgling state may be in for trouble if the Serbian Radical Party wins the vote.

"In these elections, I'm expecting that hopefully the democratic side of Serbia will win. But if the Radicals win, I'm really expecting a destabilization and problems here," said Dejan Gvozdic, a Kosovo Serb living in the ethnically tense northern town of Mitrovica.

Kosovo remains deeply divided along ethnic lines. Ethnic Albanians account for 90 percent of Kosovo's 2 million people, but the restive Serbian minority, like the Serbian government itself, refuses to acknowledge independence.

Western officials also fear an ultranationalist victory in the Serbian elections could plunge the region back into isolation and spark new violence in Kosovo.

The situation is complicated in Kosovo because its Serbs will hold parallel local elections on Sunday. U.N. authorities contend the local poll is illegal, and Kosovo's ethnic Albanian leadership sees it as a provocation, an effort by Serbs to undermine the sovereignty of their state.

Tensions are so high that in anticipation of possible violence, and to preserve Kosovo's fragile borders, NATO will send in an additional 600 British peacekeepers to boost its 16,000-strong force already on the ground.

The extra forces are to ensure a peaceful transition of authority from the U.N. administration to Kosovo's Albanian-dominated institutions in mid-June.

Serbia has vowed to challenge Kosovo's independence internationally and undermine its government.

Within Kosovo, even Serbs are edgy, not knowing what to expect.

"I don't know what will happen if the Radicals win. Probably some trouble and the situation will be more fragile," said Andrea Mijanovic, a Serb.

"But the main thing is that Serbia's integration into the EU will be stopped. And if Radicals win, we will not see a better relationship between Kosovo leaders and Serb leaders, but a worsening time ahead of us," she said.

Soon after Kosovo's declaration of independence, Serb rioters torched border outposts and attacked peacekeepers. One Ukrainian policeman was killed and dozens of others were injured in the violence.

Although about 40 countries have formally recognized Kosovo's independence, including the U.S., Canada, Japan and key European nations, the new state remains vulnerable and is struggling to tamp down ethnic tensions.

"It's the side that descends into violence and disorder that is the loser, and both sides are quite aware of that," said Alex Anderson, who runs the Kosovo office of the International Crisis Group, a Brussels, Belgium-based think tank.

Many ethnic Albanians contend it makes no difference who wins in Serbia.

"It's easier to speak on many issues with the democratic forces. With the Radicals, that talk is much limited and could lead to tensions," said Bajram Rexhepi, Mitrovica's ethnic Albanian mayor.

"But essentially, there is no difference between Radicals and moderates when it comes to Kosovo."