The U.N. trial of two Serbian security chiefs was delayed Tuesday for the third time after a psychiatrist said one of the defendants is suffering "major depression with psychotic features" and is unfit for trial for up to six months.

Judge Patrick Robinson said Yugoslav war crimes tribunal prosecutors and defense attorneys should consider trying suspects Jovica Stanisic and Franko Simatovic separately, so that Simatovic's trial could start sooner.

A Dutch psychiatrist who examined Stanisic on Monday said he "is suffering from major depression with psychotic features and is clearly unfit to stand trial on psychiatric grounds," according to a report read in court by Robinson.

The psychiatrist said that, even if a new regime of antidepressant drugs works, Stanisic is unlikely to be fit for trial "within three to six months."

Robinson said Stanisic was rushed to a Hague hospital on Thursday suffering the acute effects of kidney stones.

Robinson did not immediately set a new date for the trial of Stanisic, who was late Serbian President Slobodan Milosevic's top security officer, and Simatovic, his deputy who ran special operations.

Instead, he told prosecution and defense lawyers to meet Wednesday to discuss options, including splitting the cases up, or delaying the trial for another six months.

The trial originally was scheduled to start March 10 and rescheduled to March 17. "We can't continue in this manner," Robinson said.

Stanisic and Simatovic face five counts of murder, persecution, forced deportations and inhuman acts linked to their role in creating, training and directing paramilitary armies that fought in Croatia and Bosnia during the 1991-95 Balkan wars. Both have pleaded not guilty.

Stanisic and Simatovic face maximum life sentences if convicted. They were arrested by Serb authorities in 2003.

Stanisic was head of the State Security Services from 1991 until Milosevic fired him in 1998. Simatovic, also 57, commanded the secret service's Unit for Special Operations that ran Serb paramilitary forces, which fought alongside the Yugoslav army during the Balkan wars.

Their indictment alleges they are responsible for hundreds of murders by notorious gangs like the Scorpions, Arkan's Tigers and Martic's Police, and for the deportation of thousands of non-Serbs in Croatia and Bosnia. The paramilitaries also allegedly took part in the massacre of some 8,000 Bosnian Muslims in Srebrenica in July 1995.