Judges at the war crimes tribunal for the former Yugoslavia have suspended the trial of ultranationalist Serb leader Vojislav Seselj.

A tribunal statement from The Hague says the judges decided that under present circumstances, it would not be possible to guarantee the security of the 10 remaining witnesses.  They said this in turn could threaten the trial's integrity.  

The judges said the witnesses have important testimony to give, but that this must be done under conditions in which they can testify freely and without constraint.

Seselj, leader of the Serbian Radical Party, is on trial on charges of war crimes and crimes against humanity during the Balkan conflict of the 1990s.

Prosecutors filed additional charges last month, citing Seselj for contempt for revealing the identities of three protected witnesses who testified at his long-running trial.

Authorities say the defendant disclosed witness identities in a book he authored.

Some information for this report was provided by AP.