Fighting Rages as Yugoslav Leaders Urge U.N. Action

The fiercest army offensive in the six-week siege of Dubrovnik brought federal troops closer to the Adriatic port’s medieval heart on Saturday in preparation for a final onslaught on Croatian defenses.

Meanwhile, Serbia and its allies in the Yugoslav federal presidency, in a surprising shift of position, urged the United Nations to send peacekeeping troops to Croatia to stop ethnic bloodshed in the battle-scarred republic.

The Tanjug news agency said the Serb-dominated army also fought hand to hand with Croats defending Vukovar and made a “decisive” advance in the besieged Croatian stronghold on the Danube after an 11-week siege.

“Vukovar is on the brink of falling,” the town’s Croatian commander said.

Federal forces attacked historic Dubrovnik from the sea, air and land. At least three Croats and two federal soldiers were killed. The army issued an ultimatum to besieged defenders to lay down their arms. But the demand was rejected, according to a pool dispatch from reporters in the city, where most communications have been severed in the fighting.

Fighting continued despite an announcement by President Bush in The Hague that he supports European economic sanctions against Yugoslavia and that the United States will join efforts to seek a U.N. embargo on oil supplies vital to the war effort.

The Serbian-led bloc on the collective state presidency wrote the U.N. Security Council a letter demanding urgent action to end the bloodshed and calling for peacekeeping troops to be deployed in Croatia.

“The civil war in Croatia . . . threatens to spread to a wider area of Yugoslavia,” representatives from Serbia, Montenegro and the Serbian provinces of Kosovo and Vojvodina said in the letter drawn up Friday.

“U.N. peacekeeping forces would create a buffer zone and separate warring parties until the Yugoslav crisis is resolved in a peaceful, just and legal manner and with U.N. engagement.”

Croatian officials have previously appealed to the West to send in soldiers to deter further aggression. But they have insisted that any intervention be aimed at guaranteeing the borders of the republic as they stood before the war began in late June.

The wording of the appeal by the pro-Serbian members of the collapsed federal leadership made clear that they hope U.N. forces would deploy along the front lines established in battle over the last four months.