"We will fully respect the result of the referendum," said Solana, who helped set the conditions under which the plebiscite would be held.

He said it was too early to comment further, although he congratulated the Montenegrins for turning out to vote in great number: 87 percent of those eligible cast their ballot.

"This is a sign of maturity," he told reporters in Brussels.

Solana led moves in 2003 for a constitution to be drawn up for the loose federation of Serbia and Montenegro. A key part of it was an escape clause that allowed the referendum on independence after three years.

It was also the EU's top diplomat who was behind the conditions laid down for the vote; that of a 55 percent benchmark for it being accepted and on the provision that more than 50 percent of people take part.

Fair election

"The commission is pleased to note the preliminary report that the referendum in Montenegro was carried out in a calm manner and with a high turnout, which is important for the legitimacy of the vote," a spokesman added.

Officials for the Organization for Security and Cooperation in Europe (OSCE) also hailed the conduct of Montenegro's referendum as in line with democratic standards.

"Overall the referendum was conducted in line with OSCE, Council of Europe and other international standards for democratic electoral process," said Nedzat Yalcintas of the OSCE.

An EU future?

Separately, the European Commission, the EU's executive body, called on all sides in the tiny Balkans state to respect the final results. EU officials also said that it was willing to enter into negotiations for a stabilization and association agreement -- a crucial step towards EU membership -- with Montenegro. They said that the new country faced a "great challenge" to modernize its administration in order to enable it to engage in negotiations with Brussels.

Negotiations with Serbia-Montenegro were recently halted because of Serbia's failure to comply with demands by the International War Crimes Tribunal to hand over war crimes suspect Ratko Mladic, the leader of the Bosnian Serb army during the war.

Timeline for independence

Montenegrin Prime Minister Milo Djukanovic already proclaimed victory for the pro-independence camp early Monday before the official result was announced.

"Ladies and gentlemen, let me tell you that tonight, by the decision of the people of Montenegro, an independent Montenegro has been renewed," a jubilant Djukanovic told his supporters. "This is the most important day in the history of Montenegro," said the long-time advocate of independence, who added that his motive for creating a separate state was a desire not to be dominated by Serbia, which has a population more than 10 times the size of Montenegro's 650,000.

The Montenegrin parliament will now have to declare independence within 15 days of receiving the official results of Sunday's referendum. The Serbian parliament will also have to proclaim the republic's own independence. After the independence declarations, the union between the two republics automatically ceases to exist.

The breakup of the federation is unlikely to affect the two independent economic systems of Serbia and Montenegro, as they have already been operating separately for three years. Montenegro adopted the German mark and then the euro as its official currency years ago, while Serbia still uses the dinar.