Kosovo's unilateral secession from Serbia in 2008 did not violate international law, the United Nations International Court of Justice said on Thursday in a case that could have implications for separatist movements around the world, as well as Belgrade's stalled EU membership talks.

The ruling is likely to lead to more countries recognising Kosovo's independence and to move Pristina closer to entry into the United Nations.

The International Court of Justice's non-binding ruling addresses Serbia's 2009 claim that Kosovo's declaration of independence secession was a "flagrant violation" of its territorial integrity.

The United States and most other Western states recognised Kosovo's February 2008 declaration of independence but Serbia rejected it, as did its ally Russia, a permanent member of the UN Security Council.

"If the ICJ opinion establishes a new principle, an entire process of creating new states would open throughout the world, something that would destabilise many regions of the world," Serbian President Boris Tadic was quoted as saying by the Tanjug news agency. He was speaking before the court ruling.

On Wednesday, the White House said US Vice President Joe Biden reaffirmed US backing for Kosovo's independence at a meeting with visiting Kosovan Prime Minister Hashim Thaci.

Serbia lost control over Kosovo in 1999 when a 78-day NATO bombing campaign ended a two-year war between Serbia and the ethnic Albanian majority in Kosovo, and put in place a U.N. administration and a NATO-monitored ceasefire.

Since then some two million Albanians and 120,000 Serbs have lived separately in Kosovo, mutually suspicious and occasionally hostile to each other.

Belgrade has refused to recognise Kosovo's independence move and the dispute has held up its EU membership talks - and hindered its ability to attract foreign investment.

EU ministers did not debate Serbia's candidacy in June, waiting instead to see progress in relations with Kosovo, a source close to Brussels has said. The EU has told some of its diplomats to delay summer vacation plans to begin lobbying Serbia and Kosovo immediately after the ICJ ruling.

Statehood
Kosovo has been recognised by 69 nations and already functions as an independent republic with a constitution and elections.

Georgia filed a lawsuit in 2008 against Russia at the same court, saying that Russia's incursion into its South Ossetia province amounted to ethnic cleansing.

Russia, which took two decades to crush a separatist rebellion in its Chechnya province, has recognised both rebel Georgian regions as independent states but few others have followed its lead.

Spain, which has its own regions seeking greater autonomy, has already said it will not recognise an independent Kosovo.

At the start of deliberations last December, judges at the ICJ - the United Nations' highest judicial body - heard statements from 29 other nations, including Spain, the United States and Russia.

Although non-binding, the court's ruling will provide a framework for diplomats to try and establish a working relationship between Serbia and Kosovo, said Bibi van Ginkel, senior researcher at the Clingendael Institute.

"The political implications of advisory opinions can be substantial," she said.

Adding to the uncertainty, the International Criminal Tribunal for the former Yugoslavia (ICTY) on Wednesday overturned the 2008 acquittal and ordered a retrial of former Kosovan Prime Minister Ramush Haradinaj on charges of orchestrating torture, murder, rape and deportation during the war.

NATO forces in Kosovo are on heightened alert but the commander of the 10,000 troops there said there was no sign of trouble brewing.