A senior Bosnian Serb politician who reportedly ran the machinery of "ethnic cleansing" against Bosnian Muslims and Croats in northwestern Bosnia in 1992 was arrested by British NATO troops this morning and flown to The Hague to stand trial on war crimes charges.

Radoslav Brdjanin, who subsequently became a deputy prime minister of Bosnia's peacetime Serb Republic, was detained without incident in the Bosnian city of Banja Luka around 9:30 a.m., according to Maj. Gordon Welch, a spokesman for the NATO-led international Stabilization Force in Bosnia. The Agence France-Presse news service reported that Brdjanin and his wife were stopped in their car at a NATO roadblock and that he submitted to arrest peacefully.

Brdjanin is charged with planning, ordering and carrying out killings, beatings, detentions and deportations of Muslims and Croats from the region around Banja Luka during the first nine months of the 1992-95 Bosnian war, according to Welch.

The indictment of Brdjanin in March by the U.N. war crimes tribunal is among an unknown number of sealed indictments issued secretly by the panel. The tribunal's recent investigative resources have been devoted almost exclusively to prosecuting war crimes in Kosovo. On May 27, it announced the indictment of Yugoslav President Slobodan Milosevic and four of his associates on charges of crimes against humanity in the Serbian province.

Tribunal prosecutors and their spokesmen have warned that the five face additional charges--perhaps stemming from their role in the earlier war in Bosnia--and that others will be indicted in the immediate future. Chief prosecutor Louise Arbour has pressed NATO simultaneously to demonstrate to Milosevic and other war crimes suspects in Serbia that the alliance is serious about bringing suspected criminals from the Bosnian conflict to justice.

Brdjanin, a member of the Bosnian Serb parliament, will be the highest-ranking political figure among the 28 war crimes suspects in custody in The Hague. A western diplomatic source said Brdjanin "was not at the level of grand design, but the senior administrator who made things run" in the region where some of the most horrific atrocities were committed and where major Bosnian Serb prison camps were established.

Brdjanin, 47, was part of the political machine run by wartime Bosnian Serb leader Radovan Karadzic until he resigned five years ago to start his own, more moderate party. Karadzic and his military commander, Gen. Ratko Mladic, are the most prominent Bosnian Serbs named in tribunal warrants. Both remain at large. A total of 65 Serbs, Croats and Muslims are known to be under indictment for alleged war crimes in this decade's Balkan wars.

CAPTION: Brdjanin is accused of implementing "ethnic cleansing" in Bosnian war.