According to the BVD's report of its 1998 activities,"the Yugoslavia tribunal in The Hague was targeted by a number of Balkan intelligence agencies" that tried to interfere with its work.
The BVD, which is responsible for providing "an environment in which the United Nations court can function securely and safely", declined on Thursday to give more details of attempts by Balkan governments to interfere with the court's work.
Jim Landale, tribunal spokesman, also refused to comment on the BVD report. "We always decline to comment on security matters," he said.
In its report, the BVD also said it frequently provided extra security following the transfer to The Hague of suspects arrested in Bosnia by troops with the Nato-led Stabilization Force.
The agency said tight security would continue, especially if prominent suspects go on trial, in which case, "the possibility of attacks or attempts to liberate [a suspect] must be taken into account".
Set up in 1993 by the Security Council, the tribunal has indicted dozens of suspects believed to have committed atrocities in wars that have raged in the Balkans since the 1991 break-up of the former Yugoslavia.
Most recently, the court indicted Slobodan Milosevic, president of Yugoslavia, and four of his senior aides for allegedly ordering massacres of ethnic Albanians in Kosovo. All five men remain at large.
As well as the BVD's covert security operations, the tribunal is also patrolled by armed UN guards. (AP)