Yugoslav Warplanes Bomb Key Airports in Slovenia : Balkans: EC ministers announce tentative pact under which 2 republics would suspend independence bids.

Yugoslav air force fighter planes bombed Slovenia’s main airports and border crossings Friday, killing soldiers and civilians before the Belgrade government claimed it had pounded the rebellious republic into submission and would hold its fire.

A European Community delegation announced early today in Zagreb that Slovenia and a second breakaway republic, Croatia, had agreed to temporarily suspend their independence declarations. There was no official confirmation from either republic.

The EC announcement appeared to contradict Slovenian President Milan Kucan’s position going into the talks with the European delegation. He and other Slovenian authorities had said their independence was not negotiable.

However, Kucan and other officials had emphasized that their withdrawal from the Yugoslavian federation would be a gradual process. For example, they said, Slovenia will not sever itself immediately from Yugoslavia’s monetary system and international diplomacy.

Earlier Friday, the Slovenian president said on the republic’s television, “We agreed in principle on the cease-fire . . . but we do not know if the army is going to stick to the agreement.”

Explosions continued to rock this barricaded capital city even after 9 p.m., when the cease-fire was supposed to take effect, and attack aircraft screeched repeatedly over its hilltop castle and steepled churches. Toward midnight, the city became quieter.

Although fighting ceased during the night, as it had after dark on Thursday, it was not clear whether the Slovenian forces and the federal military would continue to hold their fire today.

Slovenian officials contend that the federal army is acting on its own, disregarding efforts by the powerless central government in Belgrade to bring an end to the deadly chaos that has transformed this serene territory into a war zone.

Scores of people have been killed during two days of pitched battles between the Yugoslav army and Slovenians trying to defend the independence they declared Tuesday in defiance of federal insistence that Yugoslavia stay united.

Fighting intensified Friday when the federal forces deployed combat aircraft in what were believed to be the first concerted air attacks in Europe since World War II.

Jets strafed Ljubljana’s Brnik Airport, unleashing a missile barrage that damaged a hangar and two passenger planes of Slovenia’s Adria Airways.

Rockets exploded in fireballs on the runway, blasting buses and trucks that had been scattered there by Slovenian defenders to prevent federal forces from flying in reinforcements. Jet fuel was splashed across the pockmarked Tarmac, and a dozen cars at the airport parking lot were left in smoking ruins.

Two Austrian photographers were reportedly killed when their car was struck by a missile near the airport shortly after the bombing raid, and foreigners were also among the civilian casualties of airborne attacks at two border crossings with Austria.

Reports have been contradictory on the exact number of dead and injured, but casualties were clearly in the hundreds.

Slovenian television broadcast dramatic footage of charred vehicles and bloodied victims being treated by emergency crews after the federal forces bombed the airport at Maribor, Slovenia’s main industrial city, and the few border crossings still held by rebel Slovenes.

As the deadly federal assault escalated, Slovenian President Kucan appealed to the West for help in the crisis that European neighbors had warned would be the cost of secession.

“Slovenia has found itself at war with the Yugoslav People’s Army, a war that cannot be stopped without the assistance of the international community,” Kucan wrote to officials in Luxembourg, where leaders of the 12-nation European Community met for talks dominated by the crisis in Yugoslavia.

Kucan said he hopes that the severity of the federal onslaught will persuade Western governments to “soften” their stance against Slovenian independence. No foreign countries have yet recognized the sovereignty of either Slovenia or Croatia, both of which declared their independence from the Yugoslav federation Tuesday.

EC countries had dispatched a delegation to Belgrade to meet with leaders of all six Yugoslav republics in an attempt to mediate the crisis. The EC also froze $1 billion in aid to Yugoslavia, urged an immediate end to hostilities and called on the breakaway republics to put off their secession for a three-month negotiation period.

In Zagreb, the three EC foreign ministers announced early today they had gotten an agreement under which the federal government would pull out its troops and the breakaway republics would suspend their bids for independence.

“We have been given a positive answer to three key questions: ‘Are you ready to accept a cease-fire?’, ‘Are you ready to suspend temporarily the implementation of your independence declaration?’ and ‘Are you ready to ensure the proper functioning of Yugoslavia’s rotating presidency?’ ” Luxembourg Foreign Minister Jacques Poos told a news conference.

The statement came after Poos, Italian Foreign Minister Gianni De Michelis and Netherlands Foreign Minister Hans van den Broek held two hours of talks in Zagreb with the Yugoslavian federal government and the presidencies of Serbia, Croatia and Slovenia.

But Poos cautioned that “the implementation of what we asked for must be achieved immediately,” adding that “we hope that this can open the way again for peaceful and democratic negotiations.”

“We know that we cannot solve the problems of the Yugoslav politics in one night of discussion,” Poos said. “The main aim of our mission . . . is bringing about de-escalation.”

Earlier, Slovenian Interior Minister Igor Bovcar answered appeals from the Yugoslav government and the Europeans for Slovenia and Croatia to rescind their declarations of independence by declaring: “The subjects of negotiations must be clearly spelled out, but independence is not negotiable.”

Slovenia is open to talks on resolving the conflict with Belgrade but only “after this horror is ended on Slovenian territory,” Kucan said.

Republic leaders insist that the federal troops and tanks must return to their garrisons before political consultations can begin on how to dissolve or rearrange the Yugoslav federation created in 1918.

In Washington, State Department spokeswoman Margaret Tutwiler criticized the Yugoslav army and central government for “excessive use of force and violence.” She added, however, that the United States continues to support the cause for which the army claims to be fighting--the territorial integrity of Yugoslavia within its internationally recognized borders. Washington has refused to recognize the declarations of independence of Slovenia and Croatia.

“We are strongly opposed to violence and bloodshed,” Tutwiler said. “We . . . urge all parties to cease the use of force immediately. We particularly call upon the central government and the Yugoslav army to end the bloodshed, to exercise restraint and to commence negotiations immediately.

“The United States calls on all parties in Yugoslavia to step back from the brink, to cease the use of force and to halt the implementation of all unilateral moves to alter Yugoslavia’s external and internal borders,” she added.

Tutwiler said the United States backs the European Community’s effort to mediate the crisis and supports calls for an emergency meeting of the 35-nation Conference on Security and Cooperation in Europe to discuss the situation.

She said the U.S. Embassy in Belgrade and the consulate in Zagreb have authorized dependents of diplomats to return home at once because of the growing danger of violence in Yugoslavia.

Fighting raged throughout the day as federal troops in tanks and armored vehicles battled to take control of the last of Slovenia’s 27 border crossings with Italy, Austria and Hungary.

Air assaults at the Sentilj checkpoint on the Austrian border finally ousted Slovenian rebels after pitched ground battles in which gunfire damaged nearby homes. But the punishing attack by federal warplanes killed or wounded dozens of Slovenian militiamen and foreign travelers attempting to leave the country, according to republic media reports.

Slovenian television showed a line of cars and trucks smoking from the rocket fire and Slovenian troops in full combat gear vainly attempting to retain control of the key checkpoint.

Maribor radio quoted witnesses as saying at least five people were killed during the Sentilj battle.

Federal soldiers passing in an armored vehicle also shot to death a Slovenian police officer and left his patrol car riddled with bullets, police in Maribor said.

The official Yugoslav news agency Tanjug reported ground battles on Slovenia’s borders with Italy and Austria as army columns fanned out to take control of civilian territory.

The army’s strategy appeared to be to isolate Slovenia internationally and sever its vital trade routes. Slovenia and Croatia are the most prosperous of Yugoslavia’s six republics and have traditionally been the conduit through which the federation conducts most of its business with Western Europe.

Tanjug reported that the Defense Ministry in Belgrade was ceasing its attack on Slovenia after having taken control of all international border facilities. However, the Defense Ministry said the army would return fire “if forced to do so.”

Military units stopped fighting at 4:30 p.m., according to the Tanjug statement. But aerial challenges continued over the capital hours later.

Kucan told reporters at a press conference that Yugoslav Prime Minister Ante Markovic had triggered the crisis with his order Wednesday for federal troops to secure all borders.

“But events are now unfolding with their own momentum,” the president lamented.

A Ljubljana businessman active with the civilian defense effort said the federal military action was fragmented, with some units probably unaware of the declared cease-fire and others willfully disregarding it.

“We believe that the federal government has issued a cease-fire, but the army is clearly not heeding it,” he said as a Soviet-built MIG-21 zoomed overhead.

Slovenian Defense Minister Janez Jansa said that more than 500 federal soldiers had surrendered during the offensive and that Slovenes’ resolve to resist the federal aggression was ever fiercer. Late Friday, there was a report that a general of Slovenian descent was among the federal defectors.

In Croatia, rival Croatian and Serbian militia units erected roadblocks and searched vehicles. But reports of a similar federal assault being launched there appeared to be unfounded.

Times staff writer Norman Kempster in Washington contributed to this story.