Bosnian Serbs Delay Peace Vote, Draft Conditions : Balkans: Rebel chief warns of fierce attack by NATO if Vance-Owen plan is not accepted. Any changes in pact are seen as unacceptable to world community.

Despite stern warnings of military reprisals, the self-styled parliament of Bosnia’s rebel Serbs failed Wednesday to ratify an international peace accord, drafting instead a list of conditions for its acceptance of the plan.

Parliamentary deputies were still debating the conditions early today. But these were seen as being unacceptable to the international community, whose mediators spent months working on the plan and getting the other two parties to the Bosnian civil war--the Muslims and Croats--to accept it.

Radovan Karadzic, chieftain of the rebel Serbs, opened a two-day meeting of the assembly with an appeal to its 80 or so members to ratify the Vance-Owen plan, as it is called. Under international pressure, Karadzic signed the plan at a special conference in Athens last Sunday.

“I implore you to ratify. . . ,” Karadzic pleaded. “Either we accept this plan, or we can expect fierce attacks by NATO forces.”

Karadzic’s appeal was reinforced by Serbia’s President Slobodan Milosevic. Milosevic was an early instigator of the Bosnian Serb rebellion and an overt supporter of it until trade and other sanctions imposed by the United Nations began to squeeze the Yugoslav federation, now consisting solely of Serbia and Montenegro.

“Vote for peace,” Milosevic urged in a speech to the assembly.

Another speaker, Prime Minister Constantine Mitsotakis of Greece, told the gathering: “Do not commit suicide today. The destiny of the Serbian people and of the whole Balkans is in your hands . . .”

Greece is a key nation in the region and has sought to mediate the Balkans conflict.

President Dobrica Cosic of truncated Yugoslavia warned the assembly that it faces a stark choice between a military defeat or ultimately achieving its political aims in an aura of peace.

But a hard-line mood persisted among the deputies, who have twice flatly rejected the plan, the second time just 10 days ago.

Miroslav Toholj, information minister in the self-proclaimed Bosnian Serb government, said that the Americans “are only bluffing” and will never intervene in the Bosnian civil war, as President Clinton has prepared measures to do.

Details of the proposed U.S. measures have not been made public, but they are widely believed to include air strikes against Bosnian Serb targets and a move to exempt Bosnian Muslims from the U.N. embargo on arms sales anywhere in what used to be Yugoslavia.

Late in the day, the assembly began discussing a series of conditions on which it said its acceptance of the peace plan would hinge.

Among the conditions were demands that international sanctions against Yugoslavia be lifted immediately and that territorial divisions called for in the plan be changed to guarantee permanent land links between Serb-dominated provinces.

A key element of the peace plan prepared by former Secretary of State Cyrus R. Vance, representing the United Nations, and Britain’s Lord Owen, representing the European Community, is division of Bosnia into 10 autonomous provinces. Serbs, Muslims and Croats would each govern three provinces and one, Sarajevo, the capital, would be governed by all three groups.

Fred Eckhard, official spokesman for Vance and Owen, said last week that the mediators would not reformulate their plan. And in Washington, a Clinton Administration official told the Associated Press on Wednesday that the Serbs’ conditions were impossible for the United States to accept.

Also in Washington, President Clinton consulted congressional leaders on his Bosnia policy but continued to avoid a firm commitment to seek approval from Congress before deciding to send American forces there. The leaders he met with seemed to accept that less than clear-cut position.

Bosnian Serb leaders have repeatedly complained that the Vance-Owen plan forces them to concede defeat when they have won what Karadzic called a “brilliant military victory.” The Serb forces have expelled or killed hundreds of thousands of Muslims from eastern Bosnia in a process of “ethnic cleansing” aimed at creating a Bosnian Serbia allied with Serbia.

The Vance-Owen plan calls for these ethnically cleansed regions of eastern Bosnia, which before the civil war were populated mostly by Muslims, to be designated a Muslim province.

While urging endorsement of the plan, Serb leaders admitted that it is not ideal but is the only way to avert military intervention.

As the marathon session of the Bosnian Serb parliament stretched into this morning, Milosevic returned to the podium with a renewed plea that the delegates back the Vance-Owen plan.

“Where did you get the ridiculous idea that Serbs will be the underdogs in this state?” he told the meeting, according to the British news agency Reuters.

“What we have now we cannot afford to put at stake and then lose it like a drunken poker player,” he said.

Elsewhere in Bosnia on Wednesday, Serb forces refused to allow a team of five U.N. military observers to visit the isolated Muslim town of Zepa to investigate Bosnian government charges of a full-scale Serb assault, the Washington Post reported.

Although Nikola Koljevic, the second-ranking Bosnian Serb political leader, had requested Tuesday that observers be sent immediately to check the charges by the Muslim-led Bosnian government, Frewer said Serb units told the U.N. observers they “had not received advance notification of the trip.” The U.N. observers will try again today, Frewer said.

Muslim ham radio operators said Tuesday that Zepa had been shelled for more than 12 hours by besieging Serb forces.