Amid Serb Strikes, U.N. Force Seeks a Recast Bosnia Role : Balkans: Broaden peacekeepers’ powers or pull out altogether, officials reportedly urge. Rebels step up Gorazde pounding, and a British jet is shot down.

Humiliated by Serbian rebels who have attacked Bosnian civilians and U.N. troops with impunity, officials of the U.N. Protection Force on Saturday proclaimed their mission “meaningless” if the Serbs’ aggression continues, and sources said they are considering pulling out of the Balkans.

After U.N. officials were unable to halt another Serbian onslaught against the besieged Muslim enclave of Gorazde, the civilian chief of the peacekeeping force reluctantly authorized punitive air strikes. One of two British jets answering the call for air strikes was shot down, and no Serbian targets were attacked.

But the mission chief, Yasushi Akashi of Japan, also announced that he is appealing to his U.N. superiors for urgent reconsideration of the entire mission.

Since NATO staged a limited bombing raid against Serbian heavy artillery attacking Gorazde last week, angry rebels have overrun much of the U.N.-designated safe area, fired on U.N. aircraft and soldiers, taken peacekeepers captive and expelled Western journalists.

On Saturday, a surface-to-air missile fired by Serbian nationalist forces near Gorazde downed a British Sea Harrier carrying out a search-and-destroy mission against Serbian tank units, reported Maj. Rob Annink, the U.N. spokesman for Bosnia.

The pilot ejected safely into Bosnian government-held territory, but the attack on the plane highlighted the recent harassment and menacing of U.N. peacekeepers deployed to Bosnia 21 months ago to assist in humanitarian relief.

Later, U.N. officials claimed to have arranged a provisional cease-fire for all of Bosnia on condition the Serbian rebels release all U.N. hostages and that the mission, in return, call off NATO warplanes buzzing the Gorazde region.

Western mediators and U.N. officials were expected to discuss the truce with the Serbs today.

At least 200 U.N. soldiers have been taken captive by the Serbs in retaliation for last week’s air strikes by the North Atlantic Treaty Organization. Movements are restricted for the more than 4,300 peacekeepers deployed in Sarajevo, and attacks on U.N. personnel have skyrocketed.

The British jet downed Saturday was from the British Royal Navy carrier Ark Royal on patrol in the Adriatic Sea, a NATO official in Brussels said. It was reportedly one of two planes from the ship responding to a U.N. request to attack Serbian forces besieging Gorazde late Saturday afternoon.

“The two aircraft were attempting to conduct a close air support mission (and had targeted) a tank reported to have been firing directly into Gorazde,” said a statement issued by NATO’s Southern Command headquarters in Naples, Italy.

NATO officials in Brussels said one of the Sea Harriers was hit near the target area and that the pilot managed to eject safely. He was reportedly rescued by helicopter and returned to the Ark Royal without serious injuries.

“He suffered only minor scratches,” a NATO official said in Brussels.

The NATO statement noted that neither plane actually fired at the tank.

Earlier Saturday, a U.N. plane carrying the mission commander, French Gen. Bertrand de Lapresle, was hit by three shots as it landed at Sarajevo’s airport. A French reconnaissance aircraft was also damaged by gunfire a day earlier when it flew over Serb-held positions near Gorazde.

The deliberate targeting of U.N. aircraft prompted suspension of U.N. air traffic and closure of Sarajevo’s airport, which already had been closed to relief flights as a security precaution.

Near Gorazde a day earlier, a British special forces officer was killed and another wounded when the rebels fired on their clearly marked observation vehicle with artillery and small-arms fire.

At the end of a particularly devastating day for the U.N. mission, Akashi announced Saturday night that “unless there was serious and manifest intention by the Bosnian Serb army, supported by clear action and cooperation on the ground, it would be meaningless in the present circumstances for UNPROFOR to continue to fulfill its present activities.”

The U.N. mission chief said he was “urgently reviewing the future role and status” of the peacekeeping mission with U.N. Secretary General Boutros Boutros-Ghali and that the two would soon approach the Security Council for new orders.

U.N. sources said the officials would appeal to the Security Council to either empower the mission to use force to protect its troops and endangered civilians or to pull it out altogether.

One source close to the mission command said officials were leaning toward a complete pullout of the 33,000 troops deployed throughout the Balkans.

The U.N. commander for Bosnia, British Lt. Gen. Michael Rose, denounced the situation as “untenable” after Serbian gunmen killed the British military observer near Gorazde on Friday. Rose’s appeal to Akashi to order air strikes then was turned down.

The current mission mandate charges the U.N. soldiers in Bosnia with little more than escorting relief goods. Some peacekeeping duties have been added with the designation of six U.N.-protected safe areas, including Sarajevo. But the 13,000 soldiers deployed to Bosnia are authorized to use weapons only in self-defense, which has prevented them from offering more than symbolic protection of embattled Bosnian civilians in the face of heavily armed Serbs.

Akashi conceded that the U.N. mission is incapable of fully defending Gorazde, saying too few troops are at Rose’s disposal and that U.N. officers are unclear just what parts of the safe area they are obliged to protect.

U.N. officials have privately accused Akashi of stubbornly pursuing a failed course of diplomacy with the Serbs, who have dragged out peace talks for nearly two years.

Even Russia’s special envoy to the Balkans, Deputy Foreign Minister Vitaly S. Churkin, conceded that the prospects for a peaceful solution looked bleak.

“It isn’t going very well,” Churkin told the Yugoslav news agency Tanjug after a weeklong endeavor to bring angry Serbs and the Muslim-led government back to the negotiating table. On Saturday, Russian Foreign Minister Andrei V. Kozyrev flew to Belgrade for emergency talks with Serbian officials.

Buoyed by the international community’s reluctance to use force, the Serbian rebels have challenged U.N. troops to give up on their mission. The deputy military chief, Gen. Milan Gvero, insisted that Rose be replaced before his rebels would consider resuming negotiations.

Bosnian government leaders have warned that U.N. timidity has emboldened the Serbs to further aggression and scuttled any hopes of a negotiated solution.

“How can you talk to the Serbs now, when they think they have defeated all of NATO?” asked Bosnian Prime Minister Haris Silajdzic.

Bosnian Serb commander Ratko Mladic boasted that Gorazde would be captured Saturday, a Belgrade radio station reported. His headquarters had called for Gorazde’s surrender a day earlier.

The crisis within the peacekeeping mission has unfolded in tandem with the deadly Serbian assault on Gorazde, which government officials warn is on the verge of falling.

Serbian rebels now hold all of the high ground around the city and have inflicted terror and bedlam with incessant firing into densely populated suburbs and city apartment blocks.

At least 240 people have been killed since the offensive began March 30, said Kris Janowski, spokesman for the Office of the U.N. High Commissioner for Refugees.

The refugee agency said that it has no contingency plan for evacuating Gorazde’s 65,000 residents and refugees because the enclave is surrounded by hostile Serbian territory and no other area of Bosnia is prepared to accommodate such an influx.

“I do hope some sort of cease-fire can be worked out, because the fall of Gorazde, which is packed with refugees, would cause a humanitarian disaster, most likely with tens of thousands of people fleeing in disarray,” Janowski said.

While Rose and other U.N. military officials have contended throughout the Serbian advance on Gorazde that the rebels are unlikely to conquer the enclave, those outside the doomed mission fear that the Serbs have every intention of applying their brutal policy of “ethnic cleansing” to the area supposedly under U.N. protection.

Gorazde, Zepa, Srebrenica and Bihac--all U.N.-designated safe areas--are besieged pockets of Muslim communities surrounded by Serb-held territory.

“I think the Serbs’ long-term strategy is obviously to sweep the enclaves,” one U.N. official said. “They are not interested in having these little ulcers here and there. . . . Gorazde will be a test case. If it falls, the others will follow quickly.”

More than 2 million people have already been displaced and more than 200,000 are dead or missing since Serbian nationalists rebelled against Bosnia’s March, 1992, vote for independence from Yugoslavia.

Times staff writer Tyler Marshall contributed to this report from Brussels.