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An anti-Western ultranationalist who had a surprisingly strong showing in Serbia's failed presidential vote pledged Monday to take his Radical Party to victory in next month's key parliamentary elections.

Serbia failed for a third time Sunday in just over a year to elect a president because voter turnout was below the 50 percent minimum required by the law. But in a major blow to the pro-Western authorities, Tomislav Nikolic (search) led his rival with 46 percent of the vote.

The collapse of Sunday's vote and the strong showing of Nikolic, an ally of Slobodan Milosevic, has raised new fears of instability in this volatile Balkan republic.

Nikolic told reporters that Serbia-Montenegro was slipping toward instability because of infighting and lack of leadership among the pro-Western forces that ousted Milosevic in 2000. He argued that he and his supporters could "bring order to the state," if elected.

"Maybe that time has come," Nikolic said confidently.

Any comeback of the pro-Milosevic forces would present a major setback for Washington. Serbia's reformist authorities have become a key U.S. ally in efforts to stabilize the Balkans. Nikolic has pledged to have no more extraditions of Serbs blamed for war atrocities.

Dragoljub Micunovic (search), the candidate backed by the ruling, pro-Western coalition, garnered 36 percent of the vote Sunday. The vote was considered a major test ahead of the Dec. 28 legislative elections, which were scheduled last week after the government lost parliamentary support.

Nikolic's strong showing startled organizations supporting the post-Milosevic government, such as the European Union. Cristina Gallach, an EU spokeswoman, said in Brussels, Belgium that the results "must be an alarm bell for all democratic forces in Serbia, especially considering the parliamentary elections."

Nikolic is the protege of party founder Vojislav Seselj (search), who once shared power with Milosevic and boasted close ties with right-wing figures like France's Jean-Marie Le Pen, Russia's Vladimir Zhirinovsky and Iraq's Saddam Hussein.

Nikolic said he is in constant contact with Seselj, who surrendered to the U.N. war crimes tribunal in The Hague, Netherlands, to face charges for his alleged role in the Balkan wars of the 1990s. Milosevic is also on trial for his role in the conflicts.

"The presidential elections were just a warm-up," Nikolic said. "We are certain of success (in the parliament vote)."

The failed presidential election prompted the heir to Serbia's throne, Crown Prince Aleksandar Karadjordjevic (search), to issue a statement suggesting the restoration of monarchy, which was abolished after World War II.

Serbia's junior party in tiny Montenegro, meanwhile, complained that the turmoil was interfering with the country's defense because Serbia's president must take part in the council that governs the military. Serbia and Montenegro form Serbia-Montenegro, the country that replaced Yugoslavia.

The democratic parties that once ousted Milosevic announced Tuesday that they would try to persuade Vojislav Kostunica (search) of the Democratic Party of Serbia to join forces against the Radicals.

A popular figure who spearheaded the revolt against Milosevic, Kostunica urged a boycott of Sunday's race because of his disputes with other parties in the coalition. The boycott kept many moderate Serbs away from the polls.

Kostunica's party, however, has ruled out reuniting with some of the former allies ahead of the crucial parliament vote, but said it would consider a post-election coalition in forming a new Cabinet.