The lawmakers, 242 of them present at the session, unanimously voted in favor of the constitution that will replace the current one drafted in 1990 by the autocratic leader at the time, Slobodan Milosevic.

The new constitution also needs a yes-vote in a national referendum before it becomes valid. The parliament later voted to hold the referendum Oct. 28-29.

"This is a historic day," declared Prime Minister Vojislav Kostunica after Saturday's vote. He added that the new constitution will "cement the truth that Kosovo always has been and always will be an integral part of Serbia."

Pro-Western President Boris Tadic said the constitution will define Serbia as a "modern, European state."

The hastily drafted constitution, agreed upon after a few weeks of consultations among the top leaders, was designed to underscore Serbia's opposition to possible independence for Kosovo as the result of the U.N.-brokered talks on the province's future.

The constitution also will define Serbia as an independent state for the first time since the breakup of Yugoslavia in the early 1990s.

Several hundred government critics rallied in front of the parliament building during the session to protest against the new constitution, saying that it will jeopardize Serbia's future by declaring Kosovo its own. The protesters, led by the opposition Liberal Democratic Party, announced a campaign for a referendum boycott.

Kosovo formally is a province of Serbia, but Belgrade has had no authority over the separatist region since a 1999 NATO bombing forced it to end a crackdown against the ethnic Albanian rebels and pull out its forces.

International negotiators have said that they want to conclude the talks by the end of the year, and there have been increasing signs that Kosovo will be granted some form of independence.

Inclusion of Kosovo in the new Serbian constitution will effectively rule out Belgrade's consent to Kosovo's secession, as demanded by its ethnic Albanian majority.

The urgency in bringing the constitution also is widely seen as a face-saving effort by Kostunica, who is facing a government crisis and a possible walkout of a key coalition member.

The liberal G17 Party has threatened to leave the Cabinet by Sunday over Serbia's failure to arrest top war crimes suspect Ratko Mladic and resume pre-entry talks with the European Union.

The new constitution also defines Serbia as the country of the Serb people and its other citizens, grants protection of human and minority rights, and gives a form of self-rule to the northern province of Vojvodina.