Kosovo's parliament voted unanimously to separate from Serbia on Sunday.
Members of parliament voted 109-0 for the action. Kosovo will seek to be recognized as a European country after being under United Nations control since 1999 following a civil war with Serbia. Over 16,000 North Atlantic Treaty Organization peacekeepers are stationed there.
In 1999, NATO troops drove out Serbian soldiers fighting ethnic Albanian separatists.
U.S. President George W. Bush, in Tanzania, said that the U.S. position is that the status of Kosovo must be resolved in order for the Balkans region to be stable. He noted that the U.S. strongly supports the so-called Ahtisaari plan. It calls for a form of supervised independence for Kosovo which would become a democratic, multi-ethnic society.
Ninety percent of Kosovo's population of 2 million people are ethnic Albanians.
Russia has opposed the move, saying it will set a precedent that could spur other secessionist actions around the world. The United Nations Security Council said it would hold an emergency meeting to discuss the development at Russia's request.
Today's vote is the last action in breaking up the former Yugoslavia.
Serbia denounced the declaration, with the nation's Prime Minister Vojislav Kostunica calling the new Kosovo a false state. Serbia has ruled out military action but said it would downgrade diplomatic relations with any country that recognizes Kosovo.