WASHINGTON — EVEN as the US and its allies begin beefing up the United Nations peacekeeping force in Bosnia, they confront a risk that their get-tough response to the seizure of some 300 UN troops by the Bosnian Serbs could backfire.
The strategy of the ''contact group'' -- the United States, Russia, Britain, France, and Germany -- is to use the enhanced UN force and diplomacy to pressure the Bosnian Serbs into freeing the UN soldiers they seized after NATO airstrikes last week. If that can be achieved, the hope is that a new political dialogue could begin and a pullout of the UN peacekeeping mission averted.
In a policy shift, the Clinton administration said yesterday that if asked, it would consider sending US forces to help UN troops redeploy to more secure positions. It says such an operation would be an extension of its earlier commitment to use troops to assist in any UN withdrawal from Bosnia.
By raising the likelihood of the US fighting in Bosnia, President Clinton also takes a risk that Bosnia may become a hot domestic issue driven by GOP presidential hopefuls.
The US sent an aircraft carrier, four other warships, and three amphibious-assault vessels carrying 2,000 Marines to the Adriatic Sea. Britain has dispatched the first of 1,200 troops it is adding to the 3,600 it now has with the UN Protection Force (UNPROFOR). France, which has the largest UN contingent of 3,800 soldiers, positioned an aircraft carrier carrying 2,000 troops in the Adriatic off Croatia.
''We want the Bosnian Serbs to think about getting back on an even keel and getting some negotiations going,'' a European diplomat says. But diplomats and independent analysts warn that the opposite could also happen: An isolated and irate Bosnian Serb leadership could decide to dig in deeper in what it sees as a David-and-Goliath struggle with the world's big powers.
''The Bosnian Serbs are desperate. You cannot rely on ration-ality,'' says Milos Vasic, military affairs correspondent for Vreme, Belgrade's leading independent news magazine.
Bosnian Serb leaders appear to be leaning toward confrontation. In a statement Tuesday, they accused NATO and the UN of ''siding with'' the Muslim-led Bosnian government and declared ''void'' all agreements with the UN. They said they would release hostages only if the UN renounces all military threats.
And in a letter Tuesday to UN Secretary General Boutros Boutros-Ghali, Bosnian Serb leader Radovan Karadzic warned, ''The more soldiers you will send, the more violence you will get.''
The contact group strategy was endorsed Tuesday by NATO, which refused to rule out new airstrikes on the Bosnian Serbs. The strategy calls for regrouping the 22,400-strong UNPROFOR in more defendable positions and strengthening it with more troops and equipment.
On the diplomatic front, the contact group forged ahead with an effort to persuade President Slobodan Milosevic of Serbia, the Bosnian Serbs' estranged patron, to recognize Bosnia's international borders. His acceptance would be rewarded with an easing of UN sanctions.
The US delegate to the contact group, Robert Frasure, was expected to meet today in Belgrade with Mr. Milosevic, whom Western officials believe is close to recognizing Bosnia. They say such an act would force Bosnian Serb leaders to accept a political settlement to the war because Milosevic would effectively renounce the goal of a ''Greater Serbia'' that would unite Serb-held areas in Bosnia with Serbia.
The contact group apparently hopes its strategy will add to the pressures the Bosnian Serbs already face on the battlefield. Their manpower-short army has lost territory and is being harried all along the 1,100 miles of front lines by the Muslim-led Bosnian Army and its Bosnian Croat allies.
The contact group's approach, however, is dangerously risky.
Diplomats and experts agree there is a good chance that confronted by the stronger UN contingent, Mr. Karadzic and his military chief, Gen. Ratko Mladic, could keep their hostages as insurance against new attacks. Both men may also decide they have nothing left to lose as they are to be indicted soon by the UN War Crimes Tribunal on Former Yugoslavia on charges of overseeing the ''ethnic cleansing'' of non-Serbs during the three-year-old Bosnian war, diplomats say.
Another potential shortfall in the contact group strategy is how a beefed-up UNPROFOR will help Dutch, Ukrainian, and British troops cut off in the eastern Bosnian Muslim enclaves of Srebrenica, Gorazde, and Zepa. The Bosnian Serbs control access to the enclaves, whose combined population of 115,000 depends on UN humanitarian convoys. To reach the enclaves, UNPROFOR would have to punch through the Bosnian Serb lines.
Muhamed Sacirbey, Bosnia's UN ambassador, says the contact group strategy can only work if UN commanders do not allow the holding of the hostages to deter them from their mission of defending the enclaves against Bosnian Serb attacks. Nor should they be dissuaded from responding to new provocations and outrages by the Bosnian Serbs, he says.
''You have to call their bluff,'' Mr. Sacirbey said in a Monitor interview. ''When you are playing this kind of game ... you cannot fold your hand before they do. Although they seem very belligerent and handcuff UN soldiers to ammunition dumps, I think everyone knows their hand is not very strong.''