BELGRADE, Yugoslavia -- Russia's foreign minister warned Monday that failure to accept a new Bosnia peace plan could lead to escalated warfare and even air strikes against Bosnian Serbs, but their leaders remained defiant.


The prediction came from Andrei Kozyrev after he met with Serbian President Slobodan Milosevic in a bid to pressure Bosnian Serbs to accept a plan reducing their holdings to 49 percent of Bosnia from 70 percent.


A final "no" would mean "an escalation of war, huge confrontation and the possibility of (NATO) air strikes," Kozyrev said, according to Yugoslav state radio.


"We will not take part in such a war. We take part only in (making) peace," he said, suggesting that Russia, a traditional ally of Serbia, would not come to the rescue of Bosnian Serb rebels.


Bosnian Serbs, however, appeared in no mood to relent.


Instead, their leader Radovan Karadzic called for more talks with the nations sponsoring the plan -- Russia, the United States, France, Britain and Germany.


His statement, carried by the Yugoslav news agency Tanjug, said Bosnian Serbs could accept the plan only after "unavoidable changes of the maps and an agreement about precise constitutional arrangements" guaranteeing sovereignty for a self-proclaimed Serb republic within Bosnia.


It also said Bosnian Serbs believed that foreign ministers from the mediating nations left doors open for more talks when they met in Geneva Saturday. The negotiators have emphasized, however, that they are not prepared for further talks on what they call a "take-it-or-leave-it" plan to settle Bosnia's 28-month-old war.


They agreed in Geneva to ask the U.N. Security Council for tougher sanctions against Serbian-dominated Yugoslavia, which has been accused of fomenting the conflict in Bosnia.


They also pledged to work on plans to better protect U.N. safe areas within Bosnia from Serb aggression, and to expand NATO-mandated weapons exclusion zones.


Bosnia's minority Serbs launched the war in April 1992 when they rebelled against moves by the Muslim and Croat communities to secede from Yugoslavia. An estimated 200,000 people have died.


Earlier Monday, Kozyrev told Russian reporters that Milosevic, the man most blamed in the West for inciting the Bosnian conflict, "must get Bosnian Serbs' endorsement" of the peace plan.


He said such an endorsement would allow Russia to help remove sanctions imposed on Serbia and tiny Montenegro by the United Nations more than two years ago.


On radio, Kozyrev said the plan offers Serbs internationally recognized borders that could be protected by Russian peacekeepers.


Kozyrev's comments suggested that Milosevic must cut vital support to Bosnian Serbs if he is to persuade them to agree to the plan. Milosevic has made such threats, but has yet to carry them out.