WASHINGTON -- In the wake of the U.S.-led NATO airstrike against the rebel Serbs' major air base yesterday, the Clinton administration is pressing for more allied military action but warning the warring parties not to misread the signals.
The administration is determined to curb Serbian aggression in the Muslim pocket of Bihac, a United Nations "safe area," without giving the other combatants a pretext for escalating the conflict.
It also wants to keep President Slobodan Milosevic of Serbia in the neutral corner he has occupied in recent months.
While hailing yesterday's attack on the Udbina airfield in Serb-held Croatia -- NATO's largest airstrike ever -- as "100 percent successful," senior U.S. officials said it was a carefully calibrated response to Serbian bombing of Bihac. It was not, they stressed, an attempt to impose a military solution on the crisis.
The attack was designed to put the air base out of commission by cratering the runways with minimum casualties, so as to reduce the risk of bloody retaliation, State Department and Pentagon officials said.
Secretary of State Warren M. Christopher termed the allied attack "a carefully defined military mission," adding: "They've shown that they can do that, and they can do it again if it's necessary."
He warned the Serbs not to launch retaliatory attacks on U.N. peacekeepers in the former Yugoslavia or to continue their assault on Bihac, a Muslim enclave in neighboring Bosnia.
"We will be continuing to watch the situation closely and to work with our allies on a range of options for additional NATO action to protect the safe areas and to halt the Serb offensive," Mr. Christopher said.
A senior administration official said the United States was pressing for more action against Serbian forces in the Bihac pocket, including air support for beleaguered U.N. troops there and creation of a 6-mile exclusion zone.
Senior officials said they had warned both the Bosnian and Croatian governments against interpreting the allied attack on the Serbs as a signal for them "to widen the war" in the expectation of getting increased NATO air support.
"There can be any amount of speculation about what kind of reactions all the various multiple parties in this war will have to various actions," a Pentagon official said. "Rather than speculate, I think we will find out soon enough."
One fear is that increased pressure on the Bosnian Serbs could provoke President Milosevic of Serbia into renewing his support for them. He cut off most aid in August after international economic sanctions against Serbian-dominated Yugoslavia were eased.
Lord Owen's analysis
"I think that's behind a lot of the Bosnian Serb and Croatian Serb intentions," said Lord David Owen, the European Union's mediator in the Balkans. "It is to provoke NATO and then to think that Milosevic must change his mind and must come in their support. I hope he doesn't."
But a senior Clinton administration foreign policy adviser said there was no indication of Mr. Milosevic "abandoning his current stance of divorcing himself from the other Serbs," although the official said there "could be some strains in his military people, who have been aiding and abetting the other Serbs."
More than 30 NATO planes -- 20 of them from the United States -- launched the attack on the Udbina airfield, used by the Croatian Serbs to launch bombing attacks against Bihac, 22 miles away in Bosnia, the latest focus of the renewed Serbian offensive. Three Serbian planes flying from Udbina were shot down by NATO jets earlier this year for violating the U.N. no-fly zone over Bosnia.
The NATO airstrike yesterday was requested by U.N. commanders, who are concerned about the safety of the town and the international peacekeepers in it. The strike involved British, French, and Dutch planes as well as the U.S. F-15Es, F-16Cs and FA-18Ds.
A first wave of jets used Maverick missiles and cluster bombs to suppress the airfield's defenses, including anti-aircraft artillery and surface-to-air missile batteries. The allied planes encountered missile and anti-aircraft fire, but sustained no damage, Pentagon officials said.
A second wave of attackers launched laser-guided bombs to put five craters in the runway, and ordinary bombs to damage the taxiways. During the main aerial assault on the airfield there was no sign of Serbian resistance, officials said. The Serbian pilots made no attempt to take off or to move their planes. All the NATO planes returned to base safely after the 45-minute raid.
Adm. Leighton W. Smith, NATO's commander in Southern Europe, estimated that the Udbina airfield could be out of commission for 30 days. But the Associated Press quoted a Croatian officer as saying the airfield could be repaired as early as tomorrow.
Officials in Washington said that how long the airfield remained unusable was not the main point.
A limited objective
"The objective was a limited one," said a Pentagon official. "By doing significant damage to the airfield, we demonstrate that NATO and the U.N. command will not accept the use of that or any other airfield in Croatia for attacks on Bosnia."
"It would have been very easy to go in there and totally eliminate that airfield," said a U.S. Air Force commander, adding that the decision to limit the strike was made by the U.N. and NATO commanders in Europe.
While members of the U.N. Security Council met over the weekend to authorize the NATO airstrike in the Krajina region of Croatia, the military commanders were planning the raid, which was delayed from Sunday because of bad weather.
The NATO pilots were ordered not to hit Serbian aircraft or other airfield installations, such as fuel dumps, to minimize the risk of casualties and to reduce the threat of Serbian retaliation or reaction from other parties to the conflict.
U.S. officials said they had no information on Croatian claims that civilians in two nearby villages were injured in the raid.
Mr. Christopher met yesterday with NATO Secretary-General Willy Claes, who has criticized the recent Clinton administration decision not to enforce the U.N. arms embargo against the Bosnians.
European nations that have contributed troops to the U.N. peacekeeping force in the former Yugoslavia complain that easing the flow of arms to the Bosnians could increase the violence and put peacekeepers in greater danger.
Rift over arms policy
The issue has strained the NATO alliance and thrown the U.S. commitment to European security into question.
The Clinton administration ended its monitoring of the arms embargo in the face of congressional pressure to unilaterally lift the U.N.-mandated embargo to enable the Bosnians to defend themselves.
Mr. Claes warned yesterday that any unilateral move by the United States to lift the arms embargo "will be followed immediately by withdrawal of the Western European [peacekeeping] troops.
"I am ready to come back, if necessary, every month to the Congress in order to tell congressmen that I believe that a unilateral lift of the arms embargo would be a mistake for several reasons," Mr. Claes said.
But Mr. Claes, seeking to minimize the trans-Atlantic policy difference, said yesterday's U.S.-led airstrike showed "that NATO is not dead at all."
"Those who pretend that America is not willing to go on, to cooperate, are making a serious mistake."
Mr. Christopher, asked whether a philosophical rift between the United States and Europeans remained despite yesterday's joint action, replied: "I see no such rift at all."