The Serbian Supreme Court on Monday dismissed Kosovo's unilateral declaration of independence as a null, void and illegal act, the official Tanjug news agency reported.

A statement issued by the Supreme Court said the declaration on Sunday, from the aspect of the Serbian Constitution, is an illegal act with null and void effect.

The Constitution regulates the position of the Autonomous Province of Kosovo and Metohija as an integral part of Serbia, whose territory is indivisible, the statement said.

The illegal act is contrary to the UN Charter, the final Helsinki Act, the 1990 European Charter for a New Europe, the conclusions of the Badinter Commission and the UN Security Council's Resolution 1244, it added.

Kosovo Prime Minister Hashim Thaci declared the independence of Kosovo at an extraordinary session of the Kosovo parliament on Sunday. The Serbian leadership annulled Kosovo's independence shortly afterwards.

Kosovo was a southern autonomous province within Serbia before the breakup of the Federal Republic of Yugoslavia. The Albanian-dominated region was plunged into ethnic conflicts in the 1990s.

Kosovo had been under UN administration since mid-1999, after NATO air strikes drove Serbian forces out of the province.