BELGRADE, Serbia, Dec. 5 -- Serbian authorities have stepped up the search for accused Bosnian war criminal Ratko Mladic, searching his son's house in Belgrade Thursday.

Rasim Luajic, president of the National Council for Cooperation with the Hague Tribunal, told Radio B92 that no arrest was expected immediately.

"No operation to arrest Ratko Mladic is under way, but rather a search for clues that will lead to Mladic''s arrest," he said.

Other locations in the Serbian capital were also being searched.

Mladic, a career officer in the Yugoslav army, was the son of a Bosnian Serb leader who was killed in a partisan action at the end of World War II. After the breakup of Yugoslavia, Mladic became commander of the military forces of Republika Srpska, a Serbian state in Bosnia.

In 1995, the International Criminal Tribunal for the former Yugoslavia indicted Mladic on charges of genocide and crimes against humanity for his actions in Sarajevo and in Srbenica, where thousands of Bosnian Muslim men and boys were killed.(UPI)