The hearing will resume on Wednesday at the earliest, said tribunal spokesman Jim Landale.

"Mr Milosevic has a high temperature and flu-like symptoms," he said.

Mr Milosevic, 61, was examined by doctors after complaining of feeling unwell shortly after Monday's proceedings began, said court officials.

Judge May has imposed time limits on prosecutors

His trial on 66 charges of war crimes and genocide has been repeatedly interrupted by illness.

In November, he was ordered by judges to undergo psychiatric tests, amid fears that the lengthy trial was proving too great a strain for him.

But most concern has focused on his physical health.

This is the sixth time the trial has been halted because Mr Milosevic has been too ill to continue.

Last year, doctors who carried out extensive health checks on the former president said he was facing "severe cardio-vascular risks" and recommended shorter trial days.

In the past, Mr Milosevic has suffered from high blood pressure, exhaustion, fatigue and flu.

Own defence

Mr Milosevic went on trial last February, and has insisted on conducting his own defence throughout the lengthy process.

But court officials fear that his insistence on representing himself - including vigorous cross-examination of witnesses - is proving too great a strain for him.

In November, prosecutors demanded that the defendant be obliged to take a lawyer, to speed up proceedings.

Mr Milosevic flatly refused, accusing the prosecution of trying to stop him speaking.

Long trial

The trial, expected to last at least another year, is now in its second phase, covering allegations relating to the wars in Bosnia and Croatia.

Prosecutors are due to finish presenting their evidence by May, under a time limit imposed by Judge May to stop the trial dragging on indefinitely.

But lawyers believe the repeated illness of Mr Milosevic is making it harder to meet the deadline.

After the prosecution case has been concluded, Mr Milosevic is expected to mount a lengthy defence.

Legal affairs analyst Jon Silverman say that, from the court's point of view, the worst thing that could happen would be for Mr Milosevic to die, as it would then face accusations that it killed him.