May 25, 2006 5:44 AM

PODGORICA, Serbia-Montenegro-Opponents of Montenegro's separation from Serbia have lodged formal complaints about alleged irregularities during last weekend's independence referendum, an official said Thursday.

The coalition of pro-Serbia parties known as the Bloc for Joint State, claimed that voters' lists contained names of persons not eligible to vote, said Zdravko Gvozdenovic of Montenegro's Referendum Commission.

Gvozdenovic would not elaborate, pending the Commisson's official response. If the Commission accepts the complaints, it could lead to a repeat vote in more than 100 polling stations, totaling some 100,000 voters, and possible reversal of the Sunday ballot whose preliminary results showed that the tiny Adriatic republic has opted to break away from much-larger Serbia.

The pro-Serbia groups lodged their complaints late Wednesday, just before a deadline to challenge the results.

The preliminary tally showed that in the tiny republic of 620,000 people, 55.5 percent of ballots cast were in favor of independence. That was just half a percentage point, or 2,090 votes, over the 55-percent threshold needed to validate secession under rules set by the European Union.

The leader of the anti-independence faction, Predrag Bulatovic, has warned of "negative consequences" unless the alleged irregularities are addressed. He also accused the rival side, led by pro-independence Prime Minister Milo Djukanovic of not allowing pro-union supporters to fully review the "suspicious" voters' lists.

Bulatovic has alleged that some 5,000 independence supporters, who reside outside Montenegro and therefore are not eligible voters, were "illegally included in the voters' lists" and took part in the Sunday ballot, giving Djukanovic's camp the critical edge.

The EU, the U.S. and international observers have said the vote was free and fair.

Djukanovic has repeatedly insisted that the vote was transparent and urged his opponents to give up attempts to overturn Montenegro's split from Serbia.

Serbia-Montenegro was the last union between republics of the Yugoslav federation after it collapsed in a series of bloody wars in the 1990s