Serbs Free More U.N. Hostages : Balkans: Release of 108 peacekeepers leaves 150 troops and observers still captive. Rebels say they did not capture U.S. pilot whose F-16 was shot down last week.

Bowing to international pressure, Bosnian Serbs released more than 100 U.N. hostages early today, but hours of delays suggested that the Serb leadership remained divided over how and whether to free the rest.

Two buses carrying 108 peacekeepers captured after the North Atlantic Treaty Organization launched air strikes against rebel Serb positions last month crossed the Drina River into Serbia early today, wire services reported.

The contingent included Ukrainians, Britons, French and one Spaniard, said the Bosnian Serb news agency, SRNA. It was the second release in six days but came 12 hours after it was first announced. A total of 150 U.N. peacekeepers and military observers remain hostage to Bosnian Serb forces.

Bosnian Serbs, meanwhile, told the Cable News Network that they did not capture the American pilot whose F-16 was shot down Friday. In Washington, the Pentagon said searchers were no longer receiving electronic beacon signals that had been reported emanating from the rough Bosnian terrain where the plane fell.

Today’s hostage release came in response to pressure from Greece, a traditional ally of the Serbs that is also a member of NATO, and from Serbian President Slobodan Milosevic, whose intervention was said to have freed 121 peacekeepers Friday.

The Greek defense and foreign ministers and Milosevic’s feared chief of state security, Jovica Stanisic, met for more than six hours late Monday with Bosnian Serb leader Radovan Karadzic at his headquarters in Pale to press for the release of all hostages. The Greeks met again Tuesday with Milosevic in Belgrade.

Stanisic was quoted today as saying the other hostages would be released soon.

After more than a year of claiming that he had distanced himself from the Bosnian Serbs and the war they were waging, Milosevic has stepped into the hostage crisis to reassert his authority over Karadzic. By so doing, he hopes to enhance his stature internationally and force the West to deal with him on his terms, analysts and diplomats say.

Karadzic is also hoping to gain something. He appeared to take satisfaction from the tacit recognition symbolized by the presence of the Greek leaders--a rare visit to Pale by senior-level government representatives since the U.N. Security Council banned most such contact.

“Everyone wants a reward,” said a Western diplomat in Belgrade. “Milosevic wants a reward for acting tough with Karadzic. Karadzic wants a reward for cooperating with Milosevic.”

Milosevic clearly believes that by delivering hostages to an impotent West, he is strengthening his hand while ensuring the further isolation of potential rival Karadzic, experts said.

Flush with what he perceives as new clout, Milosevic angered the Clinton Administration earlier this week during negotiations with U.S. envoy Robert Frasure. Frasure had spent weeks in Belgrade in protracted talks aimed at persuading Milosevic to recognize Bosnia. In exchange, the Serbian president would receive suspension of international economic sanctions imposed three years ago to punish Serbia for its role in fomenting Balkan warfare.

The deal had been reported near complete. But after last week’s hostage release, Milosevic started to reopen already closed topics and assert new demands, Western diplomatic sources said. The talks deadlocked, and Frasure, who represents the five-member Contact Group of mediators in the Bosnian conflict, was expected to abandon Belgrade today.

“What’s going on right now is a sort of double trade-off,” said independent political analyst Stojan Cerovic. “Karadzic is selling those hostages to Milosevic, and Milosevic is selling those same hostages to . . . the West. Karadzic asks for concessions from Milosevic, and Milosevic from the West.”

The concessions that Karadzic is seeking are not clear. He and his powerful military chief, Gen. Ratko Mladic, have insisted on assurances that they will not be targeted again by North Atlantic Treaty Organization warplanes. There was speculation that the Greeks might have delivered such a guarantee.

In Sarajevo, the besieged capital of Bosnia, where sniper fire battered residents and sent them running through city streets, 63 French peacekeepers who had been held hostage and were released last week returned to their posts Tuesday. The Bosnian Serbs had taken their weapons and white vehicles, disguised themselves in stolen French uniforms, handcuffed peacekeepers to the rebels’ ammunition dumps and, in the final indignity, shelled the route the recently released U.N. hostages had hoped to use to drive back to their base.

Yet, in another manifestation of the contradictions that have characterized the U.N. peacekeeping mission since its inception, all the former hostages could talk about was the friendliness of their captors.

“I’m angry against no one. There is no bitterness,” Lt. Philippe Beauregard said after he and 26 other weary French soldiers arrived back in Sarajevo at nearly 3 a.m. Tuesday.

The returning peacekeepers had to abandon their vehicles and, on foot, sneak down a vulnerable section of the only road into Sarajevo.

“I wouldn’t go so far as to call it a humiliation,” Cpl. Laurent Save said at Sarajevo airport, pointing to the bright side. “I didn’t think the captivity would be so short. Our release came as a surprise.”

In Washington, lawmakers from both parties were moving to restrict President Clinton’s options for the deployment of American forces to Bosnia.

Declaring that the U.N. peacekeeping effort in Bosnia has failed, Senate Majority Leader Bob Dole (R-Kan.) said he will introduce legislation within “the next few days” to limit the use of U.S. ground forces to assist a U.N. withdrawal from Bosnia.

Dole said his bill will also set conditions that would have to be met before troops could be sent, including a prior agreement with the allies on lifting the U.N. arms embargo on Bosnia’s Muslim-led government once the peacekeepers had been pulled out.

“We need to assist our NATO allies in the event of a U.N. withdrawal . . . [but] we also need to recognize that U.N. efforts in Bosnia have failed,” Dole said.

The resolution, expected to draw wide support from Republicans and Democrats, would also authorize assistance only if NATO commanded the evacuation force and if it was armed with “robust rules of engagement,” allowing for “a massive response” to any Serbian attempts to disrupt the evacuation.

The Administration on Tuesday said it had decided to “re-evaluate” its plans for sending U.S. troops to staging areas in Italy for use in evacuating U.N. peacekeepers from Bosnia, pending a review of British-French plans for creating a rapid reaction commando force.

Pentagon officials said the review was made necessary because the 10,000-member British-French force turned out to be larger than the United States had expected and may not require as much American equipment and logistic support as Washington initially had thought.

To underscore the point, the Pentagon said a “deployment” of 3,400 U.S. troops to Italy that officials had announced Monday had been downgraded to an “exercise”--meaning soldiers could be returned to Germany quickly if not needed.

Defense officials also made clear that 2,000 of the 3,400 troops already are at Vicenza, Italy, as part of a new Southern European Task Force. They said the remainder could be dispatched later this week, depending upon the re-evaluation.

Times staff writers Art Pine and Michael Ross in Washington contributed to this report, as did Times special correspondent Samantha Power in Sarajevo.