U.S. Jets Down 4 Bosnian Serb Planes to Enforce ‘No-Fly’ Zone : Balkans: The intruding aircraft had reportedly bombed Muslim targets. The confrontation is the first use of Western force in the conflict and NATO’s first offensive action ever.

Adding a new dimension to the war in Bosnia-Herzegovina, U.S. Air Force planes early Monday attacked six Bosnian Serb aircraft, shooting down four of them after they had reportedly bombed targets in government-controlled areas of the country.

According to officials at NATO headquarters here, the attack was carried out by two U.S. F-16 planes enforcing a U.N.-imposed “no-fly” zone, which has been in effect over Bosnia since October, 1992.

“The pilots issued, in accordance with their rules of engagement, two ‘land or be engaged’ orders to the aircraft which ignored them,” declared a North Atlantic Treaty Organization statement. “The NATO (F-16s) engaged the planes, shooting down four of them.”

At a news conference later in the day at NATO’s Southern European headquarters in Naples, Italy, U.S. Adm. Jeremy Boorda cited unconfirmed reports that just prior to the F-16s’ attack, the Serbian planes had dropped as many as eight bombs, hitting a hospital and a storage facility.

The NATO attack marks a series of important firsts:

* After seemingly endless diplomatic activity to end the messy Balkans war, Monday’s attack has for the first time brought Western military power to bear in Bosnia.

* After more than 1,000 previous Serbian violations of the “no-fly” zone, NATO aircraft used force for the first time to enforce the 16-month-old U.N. ban.

* For the first time in its 44-year history, NATO forces were engaged in offensive military action.

“We have to make clear that NATO has a new task of ensuring stability and peacekeeping within the United Nations framework,” NATO Secretary General Manfred Woerner said Monday evening.

The incident reportedly occurred over Bosnian government-controlled areas in the center of the republic, after the Bosnian Serb craft took off from the city of Banja Luka, about 80 miles northwest of Bosnia’s capital, Sarajevo.

An alliance spokesman said the F-16s returned safely to their base at Aviano, Italy, but the fate of the Serbian aircraft crews was unknown.

Speaking to reporters as he departed the White House for a trip to Chicago and Pittsburgh, President Clinton stressed that Serbian planes had been warned before the attack. “Every attempt was made, to the best of my information, to avoid this encounter,” he said.

British Prime Minister John Major, in the United States for talks with Clinton, was more forceful: “There was no reason for these planes to be there. They were there for hostile intent.”

While Monday’s attack has certainly altered the military equation of the Balkans war, it was not immediately clear exactly how it will affect efforts to end the conflict. Bosnian Serb forces were reported to have launched a fierce assault on the northern city of Tuzla after word spread that four of their aircraft had been downed.

Although Western news agencies in Tuzla reported heavy shelling late Monday morning, it remained unclear whether the NATO action would prompt a wide-scale intensification of assaults around the republic.

Some analysts expect NATO’s action to have a deterrent effect on Bosnian Serb forces, who have been allowed to violate numerous U.N. Security Council resolutions with impunity, which has emboldened them to press on with their offensives.

Interviewed on German television Monday evening, Woerner supported this view. The incident involving the NATO attack “will not lead to an escalation but just the opposite,” he said. “People will learn to respect NATO.”

The downed planes were identified by NATO officials here as Soko G-4 Galeb attack aircraft and were believed to be part of the Bosnian Serb air force. The Super Galeb was designed as a trainer by the former Yugoslav government. But since the breakup of Yugoslavia began nearly three years ago, it has been used by Serbian forces in Slovenia in 1991 and in the bombardment of the Croatian port of Dubrovnik the following year.

The International Institute of Strategic Studies in London reports that Bosnian Serb forces have about 20 such aircraft. “They haven’t been flying a great deal, and of course that reduces the performance of their pilots,” noted Ken Petri, an air warfare specialist at the institute. “They were certainly no match for the F-16s.”

Start to finish, NATO’s first-ever attack lasted a total of 20 cold minutes.

The Serbian jets had barely gotten off the ground from Banja Luka when they were sighted and pursued, according to Boorda, who, as commander of Operation Deny Flight, has overall responsibility for enforcing the “no-fly” zone. Boorda told a news conference at his headquarters in Naples that the American jets were not fired upon. The American pilots did not see any of the pilots of the four destroyed planes eject, he said.

American military officials and diplomats, unable to fully explain why the Serbs launched an aerial raid in violation of NATO’s “no-fly” zone, surmised that it may have been part of a concerted effort to test NATO’s resolve.

The Bosnian Serb planes that set out to bomb a Muslim-run munitions factory--their first fixed-wing aircraft to break the “no-fly” zone since it was set up 16 months ago--were antiquated, conspicuous and incapable of defending themselves against the NATO fighters patrolling the zone, U.S. military officials said.

Officials speculated that the mission could have been merely a foolish move by a sometimes disorganized Serbian force. Or, more seriously, it might have been an calculated effort to see whether NATO would look the other way rather than fire in anger for the first time in the organization’s 44-year history.

State Department spokesman Mike McCurry said that the speculation among Administration officials “ranges from clear stupidity to some effort to test” NATO’s resolve.

“If it was a test,” said Boorda, “I think we passed a quiz. I hope that there is also a lesson learned. When you take a test, you get a critique at the end. And the critique here is that you really ought not to violate the ‘no-fly’ zone.”

McCurry said U.S. Ambassador Thomas R. Pickering in Moscow gave a complete briefing to the Russian Foreign Ministry on details of the combat. Although Russia generally sympathizes with Serbia, McCurry said the Russians did not criticize enforcement of the “no-fly” zone.

U.S. Balkans mediator Charles Redman telephoned Russian Deputy Foreign Minister Vitaly S. Churkin to provide a status report on peace talks being held in Washington among the Muslim-led Bosnian government, Bosnian Croats and the Croatian government.

Officials said the Clinton Administration, realizing that Russia is extremely sensitive about the Bosnian conflict, is determined to keep Moscow fully informed about U.S. and NATO action in the crisis.

The decision to use armed force against Bosnian combatants for the first time in the 23-month-old conflict seems to have caught all factions on the ground by surprise. International aid agencies had just within the past few days sent back the dozens of Bosnian field workers evacuated as a safety precaution before a Feb. 21 NATO deadline for withdrawal of Bosnian Serb artillery from around Sarajevo.

NATO had threatened to launch air strikes against any heavy guns left within the 12-mile exclusion zone, and senior Bosnian Serb military officers had warned that they might retaliate by taking aid workers or foreign journalists hostage in the event their weapons were hit.

“I don’t think anybody had advance notice this was going to happen,” Ron Redmond, spokesman for the Office of the U.N. High Commissioner for Refugees office in Geneva, replied when asked if relief agencies had been warned that NATO planned to finally enforce the “no-fly” order.

The refugee agency, which delivers humanitarian aid on which virtually all of the surviving population of Bosnia depends, immediately suspended its airlift of food into Sarajevo and all road convoys that would have passed through Serb-held territory.

More than 1,000 violations of the “no-fly” zone have been recorded by NATO warplanes since they began four-times-daily patrols over Bosnia last April in a symbolic show of enforcement.

The air-exclusion zone over Bosnia actually dates to October, 1992, when the Security Council imposed the “no-fly” order to express international condemnation of Serbian aggression. Only Bosnian Serb forces had combat aircraft at that time, although Bosnian Croats have since acquired helicopter gunships from their patrons in neighboring Croatia.

The International Committee of the Red Cross also received no advance warning that NATO planned to target violators of the “no-fly” zone. It canceled all aid convoys and ordered its 25 field workers in the Banja Luka area to stay in the office, said Jetta Sorensen, public affairs officer for the Red Cross in the Croatian capital, Zagreb. She expressed concern for relief workers’ safety in the wake of the NATO attack in one of the Serb-held regions most hostile to foreigners.

Banja Luka is the most ardently nationalist stronghold in Bosnian Serb-held territory, which now spans 70% of the former Yugoslav republic. It has been the launch pad for some of the most vicious applications of “ethnic cleansing,” including mass incarcerations of Muslim males and organized rape campaigns against Muslim women.

The headquarters of the U.N. Protection Force for the Balkans, in Zagreb, was thrown into disarray by NATO’s sudden action, sources at the sprawling compound said. One senior officer confirmed that the U.N. mission was not consulted prior to the NATO decision to shoot at the Bosnian Serb aircraft.

“We learned about it as it happened,” the officer said of mission headquarters in Zagreb. “It all came down in a couple of seconds.”

But after months of daily flouting of the U.N. “no-fly” order, suspicion surfaced that NATO’s belated move to enforce the ban on combatant air operations was exercised at least in part out of frustration with the thwarted alliance effort to lift the artillery cordon strangling Sarajevo.

Since the Feb. 21 deadline expired a week ago without full compliance, mortars have been fired within the allegedly demilitarized zone and new discoveries of Serbian rebel weapons caches have been made by the dozens each day.

Such motives were hotly denied by a senior NATO official here, who claimed that on previous violations, it was unclear what the Serbian aircraft were doing and that on all previous occasions they immediately obeyed warnings to land. “Today was different,” the official said. “NATO pilots clearly saw these aircraft were bombing, and then they disregarded the warnings to land.”

Boorda also noted that the incident marked the first time there had been any long sorties by warring factions since the U.N.-ordered air embargo of Bosnia-Herzegovina began. “We hope this will be the final such incident of this tragic war,” Boorda said.

Although Security Council Resolution 816 clearly authorized NATO to fire on aircraft violating the “no-fly” zone, NATO officials had in practice deeded the final decision on whether to use force to the commander of the U.N. Protection Force.

A senior source at mission headquarters in Zagreb said NATO had at least twice sought permission to shoot down aircraft in clear violation of the “no-fly” order but that the move had been vetoed by the U.N. force commander because the use of force against any one side could endanger some of the 12,000 U.N. troops on the ground in Bosnia.

U.N. troops are charged now only with escorting humanitarian aid in Bosnia and have no peacekeeping or peacemaking responsibilities. Because they are deployed with a mandate to remain neutral, any move by NATO or a U.N. member state to take action against any particular faction raises concern that the lightly armed troops could become targets for retaliation.

Marshall reported from Brussels and Williams from Vienna. Times staff writers William D. Montalbano in Rome and Richard Serrano in Washington contributed to this report.

Showdown in the sky

The five-minute attack was the first use of military force by NATO in its 44-year history. It began at 9:45 p.m. Pacific time Sunday.

HOW: Bosnian Serb attack aircraft were intercepted by U.S. F-16s and shot down after two warnings, U.S. and NASTO officials said. One U.S. F-16 shot down three Serb planes with air-to-air missiles and a second F-16 destroyed a fourth. Two other Serb planes escaped.

WHERE: The incident took place in central Bosnia and involved Serbian planes from Banja Luka. The U.S. planes are based at Aviano Air Base in Italy.

WHY: Sources said the Serb planes had tried to attack a munitions factory. The incident came in the U.N.-sanctioned “no-fly” zone, which covers all of Bosnia. The 16-nation North Atlantic Treaty Organization agreed last April to enforce the zone to keep the skies over Bosnia clear of all non-authorized flights.

GOING HEAD TO HEAD

F-16C Fighting Falcon

Purpose: Multi-purpose tactical fighter-bomber

Maximum speed: Over 1,000 m.p.h.

Weapons: Can carry 12,000 pounds of nuclear or non-nuclear weapons

Soko G-4 Super Galeb

Purpose: Yugoslav-built light-attack aircraft

Maximum speed: 565 m.p.h.

Weapons: Two 23mm cannons; can carry 1,870 pounds of bombs