``The ring is closing around the Yugoslav forces,'' NATO Secretary-General Javier Solana said.
State-run Serbian television, meanwhile, claimed that Yugoslav forces had cleaned out key strongholds of the rebel Kosovo Liberation Army. And two trains jammed with more than 10,000 refugees arrived yesterday at the Macedonian border, where U.N. refugee officials described scenes of pandemonium.
``People were . . . crammed onto the train like sardines,'' said Judith Kumin, a spokeswoman for the U.N. High Commissioner for Refugees in Geneva. ``Two old people died in the crush, and three women gave birth.''
Clinton, speaking after a meeting in Norfolk, Va., with families of some U.S. service men and women involved in the air campaign, condemned an announcement on Yugoslav television that the three soldiers captured Wednesday near Yugoslavia's border with Macedonia would be tried today in a military court, and pledged to work for their release.
``There was absolutely no basis for them to be taken,'' Clinton said. ``There is no basis for them to be held. There is certainly no basis for them to be tried.''
U.S. and NATO officials said the capture of the soldiers - identified as Sgt. Andrew A. Ramirez, 24, of Los Angeles; Staff Sgt. Christopher J. Stone, 25, of Smiths Creek, Mich.; and Spec. Steven M. Gonzales, 21, of Huntsville, Texas - would not deter the air campaign. They argued that the bombardment was working against Milosevic's forces, and U.S. officials committed 13 more F-117A stealth fighters to the effort.
With no direct diplomatic relations with Yugoslavia, the United States worked through Swedish diplomats in Belgrade to check on the Americans and to work for their release. U.S. Secret Service agents and State Department officials had closed the Yugoslav Embassy in Washington and expelled its remaining diplomats, a week after the Yugoslav government severed formal relations with the United States.
Gen. Henry H. Shelton, chairman of the U.S. Joint Chiefs of Staff, who also was in Norfolk, sidestepped questions about any possible attempt to rescue the soldiers. ``We have some initiatives that are ongoing at this particular time,'' he said, ``and that's as much as we want to say about that.''
``We've all seen their pictures. We don't like it. We don't like the way they're treated. And we have a long memory about these kinds of things,'' said a stern Gen. Wesley Clark, the U.S. Army officer serving as the supreme allied commander of NATO forces in Europe.
International law requires that prisoners be provided food, clothes, housing and medical care, and that they are protected against violence, coercion or threats. They should be required to provide only their name, rank, serial number and date of birth.
State Department spokesman James Rubin said the Geneva Convention also prohibits putting prisoners on trial, as the Serbs threatened to do with the Americans.
``The fact is it was illegal for them to be abducted, and they were performing a mission in a neutral country,'' Rubin said. ``There is no basis for their detention. And under the Geneva Convention, to subject them to some phony trial . . . is just ridiculous.''
While U.S. officials worried about the captured Americans, they also were concerned that too much concern for their welfare could endanger the thin popular support for the air campaign, which began March 24.
``It's awful they've been taken. But they are of absolutely no strategic value. They don't know anything, like a pilot might about targets,'' said one Pentagon official who spoke on condition of anonymity. ``All that can happen now is that their capture makes the country mad.''
Clinton urged Americans not to focus only on the plight of the three soldiers. He urged them to also remember the fate of the ethnic Albanians being killed or driven from their homes in Kosovo by the Serbs.
``I ask you also to resolve that we will continue to carry out our mission with determination and resolve,'' he said.
U.S. and NATO leaders tried yesterday to paint the NATO campaign as effective and successful despite continuing reports of Serbian aggression against ethnic Albanians and the mass exodus of Albanians into neighboring countries.
``We are making progress,'' said U.S. Defense Secretary William S. Cohen. ``And we intend to stay the course.''
In a dramatic demonstration that the air war has expanded beyond the original limited range of military targets, allied strikes destroyed a bridge over the Danube River used mainly by civilian traffic in the city of Novi Sad. Residents told reporters two missiles hit the bridge's main support columns dead-on and the wreckage collapsed into the muddy river, disrupting navigation on the river, a major transportation artery for central Europe.
The Pentagon spokesman, Kenneth Bacon, said yesterday's bombing runs included the first attacks on the smaller units of troops believed to be carrying out the expulsion of Kosovo's ethnic Albanians.
Bacon said warplanes attacked a number of armored personnel carriers in central Kosovo. Also struck yesterday, he reported, were lines of communications and a major fuel facility, a strike aimed at limiting the mobility of Yugoslav troops.
NATO Secretary-General Solana, speaking at the daily briefing in Brussels, Belgium, said the 19-member alliance remains unified in support of the air war.
``We will be successful,'' he said, ``but we will need stamina and we will need determination.''
Clark, NATO's supreme commander, said the alliance was ``having results against forces on the ground, including some of the forces engaged in operations in and around the Pagorusa Valley,'' where Serbs were battling the rebel Kosovo Liberation Army. He said NATO forces had done ``substantial damage'' to the Serbian military.
And he challenged widespread reports that the Serbs were ``cleansing'' Kosovo of Albanians through murder or exile so fast that NATO cannot possibly stop them in time.
``There's a little bit of mythology going on about how fast the Serb forces are working on the ground,'' Clark said. ``I would advise you not to be taken into it. We're going to continue our effort, and they're going to pay the price.''
Indeed, some of the early reports of Serbian aggression or atrocities passed on by U.S. and NATO officials appear to be wrong or exaggerated.
In one example, the State Department said there was no truth to a report that thousands of ethnic Albanians were herded into a soccer stadium and were being held in a sort of open-air concentration camp.
But the fact remained that NATO forces were still struggling to knock out Yugoslav air defenses and to stop Serbian military forces who continue to attack ethnic Albanians.
After being briefed by Clinton administration officials yesterday, Sen. John W. Warner (R., Va.), chairman of the Armed Services Committee, said the attacks are starting to hurt Serbian forces, depriving them of fuel, food and ammunition.
But he predicted that Milosevic would complete his ethnic cleansing of Kosovo in a week to 10 days anyway, and that even a decision to invade with ground troops would come too late to stop the Serbian aggression.
Meanwhile, refugees continued to flee Kosovo, driven from their homes by Serbian police and Yugoslav soldiers.
Another 14,500 crossed into Albania yesterday, bringing to 100,000 the total who have arrived there since the air strikes started March 24, according to the United Nations High Commissioner on Refugees. More than half have been moved south, away from the border and closer to facilities where they can get food and shelter.
About 14,500 also fled into Macedonia yesterday, bringing to 29,000 the total who have entered. And about 7,000 went to Montenegro, raising to 27,000 the total who have fled there.
The total who have left the province - whose prewar population was about two million - is at least 156,000, officials said. But the number of new arrivals is so overwhelming that ``nobody knows how to count them any more,'' said Kumin, the U.N. refugee spokesman.
This article contains information from Inquirer wire services.