NEWS ANALYSIS : Britain, France Agonize Over Bosnia Role : Balkans: As U.N. force leaders, they face dangers whether they stay or go. Decision could come today.

Britain and France, which contribute the most troops to the U.N. Protection Force in Bosnia-Herzegovina, may decide as early as today whether to soldier on with the perilous mission or attempt a dangerous withdrawal.

British Foreign Secretary Douglas Hurd and French Foreign Minister Alain Juppe have been hand-wringing and huddling with mission commanders, Balkan powerbrokers and Western allies for the past several days as Bosnian Serb gunmen have harassed and threatened the lives of their troops.

The European diplomats face a Hobson’s choice of acknowledging failure and pulling out of the collapsing mission or trying to muddle through a few more weeks or months of frustrating operations in the midst of heavily armed rebels who have made it clear they want the peacekeepers to retreat.

With 350 U.N. troops still held hostage as insurance against bombings by North Atlantic Treaty Organization warplanes and Serbian nationalist attacks on U.N. “safe areas” intensifying, U.N. officials have begun to concede that the decision on a pullout is less a question of “if” than “when.”

Now that the threat of NATO air strikes has been all but removed, international mediators have no leverage left to pressure the defiant rebels to agree to a formula for peace proposed by the five-nation Contact Group.

And having failed to enforce U.N. Security Council resolutions aimed at protecting Bosnian civilians or to let NATO destroy rebel missile batteries that have grounded relief planes, the international community has no credible assurances of security to offer the Muslim-led Bosnian government in urging it to surrender.

That leaves the U.N. mission in a no-win situation, with no prospects for a peaceful settlement and both sides retrenching for another round of violence that will continue to escalate the risks for the 24,000 peacekeepers in Bosnia.

U.N. officials and Western diplomats here say that the chances of an official, coordinated pullout are slim in view of the stormy debate likely to precede a formal Security Council vote to withdraw.

The most likely scenario, they fear, is a piecemeal pullout in which individual countries frustrated by the repeated diplomatic failures to broker peace will succumb to domestic pressures to get their troops out of harm’s way.

Seven kidnaped Ukrainian peacekeepers were released by the Bosnian Serbs on Monday, but 350 U.N. troops remain captive, among them a Jordanian military observer with a life-threatening heart ailment.

Rebels in the nationalist stronghold of Banja Luka are refusing to release the ill officer for urgent treatment unless the mission sends another hostage to take his place.

U.N. officials have routinely condemned Serbian harassment of peacekeepers, but neither words nor threats have chastened the rebels.

A Bangladeshi soldier trapped in the besieged Bihac pocket died Saturday after being deprived of medical aid by a Croatian Serb blockade, and information on the case is being forwarded to the International War Crimes Tribunal in The Hague, mission spokesman Paul Risley said.

A U.N. spokesman in Sarajevo, the Bosnian capital, also expressed mounting frustration and an unusual degree of impatience with the dominant rebels.

Bosnian Serbs “deserve nothing but contempt” for thwarting humanitarian aid convoys bound for their victims, spokesman Thant Myint-U said.

Hurd and Juppe made a last-ditch visit to the Yugoslav capital of Belgrade on Sunday to sound out the prospects of getting Serbian President Slobodan Milosevic to push his Bosnian Serb proxies to sign the Contact Group peace plan if it were amended to allow eventual creation of a Greater Serbia.

But Bosnian Serb leader Radovan Karadzic has lately indicated that the option of uniting with Serbia is too little, too late. He now insists on more territory than the 49% the plan would give him, as well as international recognition of his conquered territory as a separate state.

U.N. and diplomatic sources here say the foreign ministers left Belgrade with little encouragement that Karadzic would be lured by an amended plan.

British Defense Secretary Malcolm Rifkind flew to the Croatian port of Split on Monday to consult with the commander of U.N. forces in Bosnia, British Lt. Gen. Michael Rose, to hear his views on the quandary over whether to leave or stay.

Rifkind warned after their talks that British troops would pull out of Bosnia if they encounter further harassment. But Rose told reporters that his country and other U.N. members have “a moral duty” to see Bosnian civilians through the winter.

Rifkind is expected at the U.N. mission headquarters here today for consultations with the top civilian and military officials, after which Britain is expected to decide its future in the peacekeeping mission.

“If Rifkind had told Rose they were pulling out, Rose would not have said what he said,” one U.N. official observed, adding that it seemed unlikely Britain would opt for an immediate withdrawal.

French troops are mostly deployed in Sarajevo, where they would be vulnerable to both Serbian harassment and Bosnian civilian efforts to prevent a retreat that would probably leave the city overrun by Serbs.

With the first snows of winter already hampering road movements, observers here predicted that it would be more likely for the French to ride out the mission until spring.

Despite the desire to persevere with humanitarian tasks such as escorting aid to hungry and isolated Muslim communities, pressures are building steadily for a withdrawal next month.

The next session of the U.S. Congress, which begins in early January, will be dominated by Republicans vowing to lift a U.N. arms embargo hampering Bosnian government defenses. Leading GOP politicians such as incoming Senate Majority Leader Bob Dole of Kansas and House Speaker Newt Gingrich of Georgia have also begun clamoring for NATO action to destroy the Serbs’ artillery and weapons plants.

As Serbian rebel fears of a comeuppance rise with the threat of a military turnaround, their determination to strike government holdouts while they have the upper hand will progressively step up the risks for the peacekeepers deployed around vulnerable Muslim enclaves.