Sarajevo Quiet After Truce Deadline : Bosnia: U.N. officials express guarded optimism about latest pact, signed by military chiefs rather than political leaders.

After heavy fighting that continued up to and past a cease-fire deadline, the big guns of Bosnia’s warring factions fell silent in the capital an hour after midnight Wednesday.

U.N. officials expressed guarded optimism that the cease-fire would work, although about 15 others have failed over the past seven months of war.

Some officials believe the Bosnia war is near equilibrium, with Serbs and Croats having captured most of the territory they want. Also, the latest cease-fire was signed by military chiefs in Sarajevo, rather than by political leaders.

“Since we got the military commanders to sign it, there is more hope,” said Gen. Satish Nambiar, head of U.N. peacekeepers in the former Yugoslav federation.

Still, Croats in Mostar, 46 miles to the southwest, reported that Serbs had hit their defensive positions with heavy artillery barrages about 10 minutes after the cease-fire deadline at midnight.

The Croats’ claim contradicted information from Bosnian commanders in Sarajevo and from Gen. Manojlo Milovanovic at Serb military headquarters in Pale, east of Sarajevo, who said Serbian guns were quiet.

The combat that broke out just before the cease-fire was the worst the shattered, freezing capital had seen in days.

Glowing tracer bullets streaked the sky after sundown. The thump of exploding mortar shells and chatter of machine guns and rifles sounded south of the Presidency Building in central Sarajevo, and machine guns could be heard firing in the western outskirts.

About 200 people who managed to get out of Sarajevo arrived weary and rattled in Belgrade on Wednesday night.

“Sarajevo is a dead city,” Mirjana Stefanovic said, fighting back tears. “The only important thing is we managed to leave.”

Shortly before the heaviest shooting in Sarajevo, the Red Cross canceled the evacuation of some residents after one of its bus drivers was wounded in a mortar attack.

The driver, Miodrag Bosiocic, was alone in the bus. He apparently was not seriously wounded. There was no indication of who fired the mortar shell.

Also Wednesday, an ethnic Albanian was killed and two Serbian soldiers were wounded in front of the Yugoslav headquarters in Pristina, the capital of the mostly Albanian province of Kosovo in southern Serbia.

Diplomats fear that an explosion of violence in Kosovo would spill over Yugoslavia’s borders and engulf Macedonia and Albania.

An army statement said the shootings occurred after three terrorists approached a guard, stabbed him with a large knife and shot another soldier in the stomach. Other soldiers returned fire, killing a 26-year-old ethnic Albanian man from Veliki Trnovac, a village north of Kosovo. The other two assailants, one of them wounded, escaped leaving a trail of blood, the army said.

A conflicting statement from the main Albanian party, the Democratic League of Kosovo, said that according to witnesses, the sentries had provoked the three passersby. A DLK leader, Saqir Saqiri, said in a telephone interview: “We are used to such daily provocations. Serbia wants provocations.”

The incident comes amid growing international concern that Kosovo could be the next region of the former Yugoslav federation to erupt in ethnic conflict. Diplomats fear that Serbian President Slobodan Milosevic, who is seen as the chief instigator of the violent breakup of Yugoslavia, may incite unrest in order to rally national support among Serbs who see Kosovo as the birthplace of their civilization.