"For the independence of Montenegro, 55.4 percent voted in favour and 44.6
were against," referendum commission president Frantisek Lipka announced.
The announcement seals the final break-up of old Yugoslavia's six republics after the blood-soaked wars of the 1990s had already led to Bosnia, Croatia, Macedonia and Slovenia leaving the federation.
The pro-independence prime minister of the tiny mountainous Adriatic state, Milo Djukanovic, had jubilantly proclaimed victory earlier Monday, declaring it as "the most important day in the history of Montenegro".
Mr Djukanovic has always said his motive for creating a separate state was a
desire not to be dominated by Serbia, which has a population of more than 10
times the size of Montenegro's 650,000.
"Let me tell you that tonight, by the decision of the people of Montenegro, an independent Montenegro has been renewed," Mr Djukanovic told his supporters.
He said 55.5 per cent of those who have voted in the weekend referendum "gave support to a renewal of the independent state of Montenegro".
"I want to congratulate the state to all citizens of Montenegro," Mr Djukanovic said at the government building in the capital Podgorica.
Celebrations
There were fireworks in the street as news came through of the preliminary referendum results showing Montenegrins to have voted for the split.
In Sunday's referendum, voters were asked to endorse or reject the question: "Do you want Montenegro to be an independent state with full international and legal legitimacy?"
Under rules agreed with the European Union, more than 55 percent of Montenegro's 485,000 eligible voters had to back independence to create the world's newest mini-state.
Around 56.3 percent of the tiny Balkan state's voters chose to separate from Serbia, according to first estimates by an independent monitor, the Centre for Free Elections and Democracy.
The estimate, based on a partial count, shows the vote narrowly clearing a hurdle required for independence -- at least 55 percent of voters must be in favour for the referendum to be valid.
Car drivers beeped their horns and fireworks were set off in the streets of the capital Podgorica as the news was announced.
If the result is confirmed, it would mean Montenegro, and by default Serbia, would become the world's newest states.
It would also mark the final break-up of the old Yugoslavia after the blood-soaked Balkan wars of the 1990s in which Slovenia, Croatia, Bosnia and Macedonia left the federation.
In the lead-up to the referendum, Mr Djukanovic said 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.
Montenegro and Serbia in 2003 formed the loose union that replaced Yugoslavia, allowing either side to break free after a three-year period that expired earlier this year.
The pro-independence premier of Montenegro argues the republic will be able to speed up its European Union entry bid without Serbia.
Serbia's failure to hand over fugitive former Bosnian Serb general Ratko Mladic to the United Nations war crimes tribunal by April 30 led this month to the EU suspending membership talks.
Both sides have urged supporters to accept the result peacefully.