Clashes Peril Soviet-Backed Truce in Yugoslavia

ZAGREB, Croatia —  Fierce fighting erupted in Yugoslavia on Wednesday, and the rival republics of Croatia and Serbia set conditions that put in doubt new peace moves brokered by Soviet President Mikhail S. Gorbachev.

Croatian radio said mortar and artillery battles raged in the northeast and center of Croatia despite a cease-fire agreement signed by the leaders of Croatia and Serbia after meeting Gorbachev in Moscow on Tuesday.

At least seven people were reported killed.

Serbia and its allies in a collective state presidency boycotted by their rivals said decisions to be made in European Community peace talks in The Hague on Friday will not be legitimate because the presidency has not been invited.

Serbia and its allies--Montenegro and the Serbian provinces of Kosovo and Vojvodina--said in a letter to the leaders of Friday’s EC conference on Yugoslavia that the presidency will not accept any decisions made there.

EC negotiators and the six Yugoslav republics will take part in the talks. The EC has not invited the national presidency because the EC does not recognize decisions of a body boycotted by Croatia, Slovenia, Bosnia-Herzegovina and Macedonia.

And in a further blow to peace efforts, Croatia toughened its stance on peace negotiations by refusing to lift blockades of federal military bases until the army starts withdrawing troops from the rebel republic.

“A lot more people are going to die before there is any peace in Yugoslavia,” a Western diplomat in Belgrade said as hopes of peace receded further.

More than 1,000 people have been killed since Croatia declared independence on June 25 and its Serb minority rebelled. Eight cease-fires have collapsed since the conflict began.

In Moscow, Russian Federation President Boris N. Yeltsin backed the peace deal signed by Serbian President Slobodan Milosevic and Croatian President Franjo Tudjman.

The two men agreed to an immediate end to hostilities and said they will start talks within a month to sort out their differences. They also called on the superpowers and the EC to help organize the negotiations.

Despite Milosevic’s hopes of an early meeting with Tudjman, his archrival said Wednesday that immediate talks were unlikely. “If this was possible, then Europe would not be getting involved with this matter,” Tudjman told the Soviet news agency Tass.

In the Croatian capital of Zagreb, the withdrawal of federal soldiers from the Borongaj barracks is a key part of a truce that was worked out last week but has failed to get off the ground.

It has broken down because it is tied to the success of a relief convoy reaching the besieged town of Vukovar, in northeastern Croatia, with emergency aid. The convoy has repeatedly failed to get into Vukovar.