The peacekeepers said they were conducting a "routine unannounced inspection" in Bijeljina to monitor compliance with the 1995 peace agreement that ended Bosnia's bloody inter-ethnic war.

"The operation is conducted in order to disrupt the efforts of persons performing activities that impede the progress and development" of Bosnia, the NATO-led Stabilization Force (SFOR) said in a statement without elaborating.

SFOR troops carried out raids in Bijeljina last month and detained Zeljko Jankovic, a former Bosnian Serb police officer frequently described as a bodyguard of top war crimes suspect Radovan Karadzic.

Jankovic was questioned and handed over to Bosnian Serb police on Tuesday.

SFOR also searched a post office in Pale, Karadzic's wartime stronghold outside Sarajevo, last week.

In January they raided Karadzic's wartime residence in Pale but failed to find the fugitive.

Karadzic, the former Bosnian Serb political leader, is wanted by the United Nations' court at The Hague on multiple war crimes charges including genocide.

The UN tribunal's chief prosecutor, Carla Del Ponte, said earlier this month that Karadzic had found "safe haven" in the Serbian capital Belgrade but Serbian leaders angrily dismissed her claims.

WAR.WIRE