BUILDING PEACE IN THE BALKANS : GIs Set to Use Serbia Airport as Staging Area : Military: Offer of Belgrade facilities is another effort by Bosnian Serb’s ally Milosevic to get in NATO’s good graces.

In a new twist in the already bewildering Balkan conflict, U.S. military forces will begin using airport facilities in Belgrade--the capital of Serbia--as a staging area for American troops being sent to Bosnia for peacekeeping duty, the Pentagon said Wednesday.

Three or four huge U.S. Air Force C-17 transport aircraft, loaded with troops from the 1st Armored Division in Germany, are to make the first landings in Belgrade and the rump Yugoslavia today, to be followed by regular military flights later, U.S. officials said.

The use of the capital of the former Yugoslav federation marks another effort by Serbian President Slobodan Milosevic, who played a key role in the Dayton, Ohio, peace negotiations, to cast himself as an ally of the West in helping North Atlantic Treaty Organization troops enforce the peace accord.

Milosevic has been blamed for starting the strife that has torn Bosnia-Herzegovina apart during most of the past four years, first by encouraging Serbian nationalists to launch a secessionist war there and then by supporting rebel forces with weapons and supplies.

Analysts say Milosevic’s recent bid to play peacemaker is part of an effort to win removal of the economic embargo imposed on the rump Yugoslavia--made up of Serbia and tiny Montenegro--by the United Nations in 1991. Since the Dayton accord was initialed last month, the embargo has been partially lifted.

Pentagon officials also announced that the United States will send two counter-battery radar teams--both staffed by American soldiers--to Sarajevo, the Bosnian capital, for 30 days to help protect the city during the early days of the NATO peacekeeping mission there.

The radar units can track a projectile fired by enemy artillery back to the gun from which it came and direct U.S. artillery fire so it destroys the enemy howitzer within a few seconds after the shot is fired. The system has been in the U.S. arsenal since the late 1970s.

U.S. Air Force Lt. Gen. Howell M. Estes Jr., operations director of the Joint Chiefs of Staff, flatly denied allegations that the stationing of the two units near Sarajevo, outside the U.S.-run sector in northeastern Bosnia, constitutes “mission creep,” or a broadening of the U.S. mandate in the war-torn country.

Estes told reporters that the reassignment had been ordered by U.S. Adm. Leighton W. Smith, commander of the peacekeeping operation, and would not leave U.S. forces in any extra danger. He said the units will be shipped back to Tuzla, the headquarters of the U.S. sector, after 30 days.

The push to use Belgrade as one of the airports at which U.S. troops will be landing followed a series of snags that have delayed the deployment of American peacekeeping troops into the area around Tuzla.

First, snowstorms impeded air traffic at other airports, preventing U.S. transport planes from landing. More recently, weather has slowed construction over the Sava River between Croatia and Bosnia of a pontoon bridge that officials had hoped to be using as a major highway for tanks and armored vehicles.

Estes said U.S. soldiers landing in Belgrade would travel by road through Serbia and Hungary and then down to Tuzla.

“The road from there to Tuzla is good, and we might as well take advantage of it,” he told reporters here Wednesday.

Officials said U.S. Army Gen. George A. Joulwan, NATO’s supreme military commander, is expected to arrive in Belgrade today to help kick off the new routing. He also may meet with Milosevic to discuss the remainder of the deployment.