U.S., Allies Unveil Croatia Peace Plan : Balkans: But Serb rebels in Krajina refuse to even look at envoys’ autonomy proposal.

ZAGREB, Croatia —  In an urgent attempt to avoid another war in the Balkans, the United States and its allies unveiled an autonomy plan Monday for Croatian Serbs whose 10-month-old cease-fire with the Zagreb government is in danger of collapsing.

But, handing a stunning rebuke to the international envoys who drafted the plan, the Serbs refused to even look at the 42-page document.

“This is something that makes the situation in Croatia much more dangerous,” Peter Galbraith, the U.S. ambassador to Croatia, said in a telephone interview from Knin, the Serbian rebel stronghold in southern Croatia where he and the other diplomats had traveled to deliver the proposal.

“We’ll have to reassess,” he said. “There is only so much the international community can do. And unfortunately, time is running out.”

The plan--effectively stillborn--had been seen as a last-ditch effort to prevent war between the Croatian government and the Serbian rebels who control nearly one-third of the country. Fear of renewed fighting grew following President Franjo Tudjman’s decision earlier this month to expel 14,000 U.N. peacekeepers from Croatia when their mandate expires March 31.

For three years, the U.N. mission has served as a buffer between Croatian forces and the Serbs, who control a long, mountainous swath of territory they seized during the Serb-Croat war of 1991, one of a brutal series of ethnic conflicts that have devoured the former Yugoslav federation.

Tudjman’s planned ejection of the U.N. monitors was widely viewed as a signal of the government’s intention to take back the land, which borders Bosnia-Herzegovina and is known as the Krajina region, that the Croatian Serbs now control.

Hoping to avoid wider conflict, diplomats from the United States, Russia and Europe worked for months to draft a political settlement that includes autonomy for some Serb-controlled regions. Galbraith, Russian Ambassador Leonid V. Kerestedzhiyants and three representatives of the European Union and the United Nations presented the plan to Tudjman at the presidential palace Monday morning.

Later Monday, they traveled to Knin. The Serbs received the envoys but refused to accept a copy of the plan, saying that they hoped their recalcitrance would intensify pressure on Zagreb to allow the U.N. peacekeepers to remain in Croatia, Galbraith said.

“We told them their tactic would be counterproductive,” he said.

The plan, a copy of which was made available to The Times, would grant political autonomy to Serbs living in the portion of central and southern Croatia that they currently control, an area where they represented an ethnic majority before the war.

It would set up a state-like region with its own “president,” legislature, judges and police force. Regional authorities would be allowed to tax residents, who would in turn be exempt from national taxation. The area could have its own flag and language.

But two fertile, oil-rich areas of north and northeastern Croatia, also controlled by the Serbs, would not be granted autonomy and would be re-integrated into Croatia during a period of up to two years.

Even before the Serbs’ outright refusal to consider the plan, neither they nor the Croatian government was expected to be delighted with its elements. And both sides have vowed to return to the battlefield if necessary.

Tudjman said last week that any political settlement to the conflict must come within the bounds of the national constitution. And the Serbs continued to insist on their own state.

Milan Martic, the self-styled leader of the Croatian Serbs, said over the weekend that any plan that includes a loss of independence “is out of the question.”

“We are ready for peace,” Martic told Yugoslavia’s Tanjug news agency, “but also for war.”

The 1991 conflict began after Serbs rebelled against the Croatian republic’s decision to break away from the Yugoslav federation. Backed by the Yugoslav army, the Serbs quickly overpowered the lesser-armed Croats until an agreement brokered by former U.S. Secretary of State Cyrus R. Vance ushered in the U.N. monitors in 1992. Nearly 10,000 people died in the war, and tens of thousands were driven from their homes.

A formal cease-fire was signed in March.