BERLIN -- The vehemence of the Bosnian Serb response to the latest NATO airstrikes indicates how fearful the Serbs have become that the war is at long last turning against them, analysts say.
Faced with dwindling supplies of arms and fuel and a rejuvenated opponent, the Bosnian Serbs had reason to be anxious even before the last week's NATO air attacks, which destroyed about 10 percent of the Serbs' ammunition reserves.
"They're very desperate," said Paul Beaver, a Balkans military analyst with Jane's Defense Weekly in London. "They are rats in a corner. They are war weary, and they are more or less cut off."
The Serbs have broken no new ground in their responses to NATO, which included stepped-up shelling of civilians and the taking of United Nations troops as hostages. The Serbs had seized several Canadian military observers as "human shields" last fall after a NATO air attack in northwest Bosnia. And the Serb shelling of civilians is as old the war.
But almost everyone has been surprised by how many hostages have been taken -- 379 U.N. soldiers and military observers so far, after yesterday's addition of a dozen Ukrainian U.N. soldiers. And the magnitude of that action seems to highlight Serb fears.
"The very act of hostage-taking was an act of desperation," said Milos Vasic, a military analyst with Vreme, an independent Belgrade weekly. "Time is against the Serbs, and you can see that in the field."
The Serbs are becoming more isolated, politically and economically. Their enemy, the Bosnian Muslims, are slowly gaining strength and confidence.
"They have been under terrible pressure all over their front line," Mr. Vasic said of the Serbs. "The Bosnians have learned how to make the Serbs stretch their lines. They are hitting from the inside and [Bosnian Serb Gen. Ratko] Mladic has to keep moving his troops around the outside, on a long perimeter. It has become a sort of war of attrition."
Great Britain, France and the United States have pledged to strengthen the U.N. Protection Force, and they have warned that the Serbs will be held accountable for the hostages' safety.
But the Bosnian Serbs are still a formidable fighting force, sharing about 500 tanks and 1,000 artillery pieces with rebel Serbs in neighboring Croatia. The predominantly Muslim army of the Bosnian government has only about 60 tanks and about 100 artillery pieces, plus a few dozen small rocket launchers.
The Serbs also still hold about 70 percent of Bosnian territory and seem in no danger of losing any major population centers.
But the Bosnian army has survived on a shoestring for so long that its recent gains in equipment and training have significantly boosted the morale of its troops, analysts say, and that has allowed it to exploit its advantage in manpower. The Bosnian army, allied with the Bosnian Croats, has roughly 200,000 soldiers, compared to 64,000 for rebel Serbs.
The Bosnian Muslims also have better prospects for rearming as long as the worldwide arms embargo on the former Yugoslavia -- principally Serbia -- remains in effect. "A lot of countries have been turning a blind eye to arms coming into Croatia," said Mr. Beaver of Jane's, "and that means they're also going to the Bosnians."
It isn't only on battlefield where the Serbs have been demoralized. Another blow has come from Serbian President Slobodan Milosevic.
In years past, Mr. Milosevic would have responded to any attack against Croatian or Bosnian Serbs by vowing immediate aid. But he stayed notably silent in April when rebel Serbs in Croatia lost territory to Croatian government troops.
"It's always been clear that Milosevic is simply maneuvering to save his own bottom," said Patrick Glenn, an analyst with the American Enterprise Institute in Washington. Mr. Milosevic's public zeal for a Greater Serbia that would someday link Serbia to captured territory in Bosnia and Croatia has faded as his concern over the U.N.'s economic sanctions has grown.
Rather than promote a Greater Serbia, he has devoted himself to convincing the United Nations to cancel the sanctions, including an embargo on the delivery of oil.
As Mr. Milosevic has put more and more distance between himself and the Bosnian Serbs, the prospects have grown for an ever longer war.
"That's the thing that terrifies the Serbs most," said Jonathan Eyal of the Royal United Service Institute in London," -- a longer war in which they'll have to defend a very exposed and vulnerable front while the Muslims slowly acquire new weapons and organize their army better."
But if the actions of the past few days have exposed Serb fears, they have also demonstrated the enduring Serb strength when it comes to dealing with NATO and the United Nations. As in past confrontations in Bosnia, the United Nations' taste for decisive action has lasted only until the Serbs response.
"What they want to do is discredit once and for all the option of using airstrikes," Mr. Eyal said. "This has exposed the whole option of airstrikes for the ridiculous option they always were."
"There is this sense that they will once again be able to trump the U.N.," said Mr. Glenn in Washington. "They're going to play every card they have, and they don't play by any set of rules."