Former Yugoslav leader Slobodan Milosevic has been involved in bitter clashes with one of his key adversaries in his war crimes trial, Croatian President Stipe Mesic.

Mesic told Milosevic: "I'm not the one on trial"

The two men engaged in a tense and sarcastic exchange about discrimination and the right of self-determination in the former Yugoslavia.

Mr Milosevic rejected Mr Mesic's allegations that he caused the break-up of the former Yugoslavia. And he accused Mr Mesic of organising killing sprees against Serbs.

In a separate development, another main defendant at The Hague tribunal, former Bosnian Serb President Biljana Plavsic changed her plea to guilty on one count of crimes against humanity.

Plavsic denies making a deal with prosecutors

She earlier pleaded not guilty to eight charges of genocide, war crimes and violations of the rules of war, but prosecutors have now said they will drop all the other charges.

Mrs Plavsic's lawyer, Eugene O'Sullivan, denied that she had made any deal with prosecutors involving testifying against other defendants.

But the BBC's Alix Kroeger in The Hague says by pleading guilty she has in effect accepted the prosecution's case, that Bosnian Serb army units were collaborating with forces controlled by Mr Milosevic in Belgrade.

Together with Mr Mesic's evidence, our correspondent says, this seems to mark a change of fortune for the prosecution.

Fierce exchanges

Mr Milosevic began his cross-examination of Mr Mesic on Wednesday with a question-and-answer session so fast that Judge Richard May had to intervene to ask both men to speak more slowly for the court interpreters.

	Milosevic charges Bosnia Genocide and complicity in genocide, crimes against humanity, grave breaches of the Geneva Conventions and violations of the laws or customs of war Croatia Grave breaches of the Geneva Conventions, violations of the laws or customs of war and crimes against humanity Kosovo Violations of the laws or customs of war and crimes against humanity Full list of charges

Mr Mesic was responsible for crimes committed by Croatian troops, Mr Milosevic argued.

"You betrayed Yugoslavia, you contributed to its dissolution," Mr Milosevic said, turning the tables on Mr Mesic, who had levelled the same accusation at Mr Milosevic on Tuesday.

On the subject of who was responsible for the break-up of the former Yugoslavia, the men - both former law students - raised their voices, agreeing that the perpetrators of crimes committed in the republics should be brought to justice.

"I'm not the person on trial," Mr Mesic shouted triumphantly.

"That's the point!" Mr Milosevic snapped back.

When accused of ordering the burning of Serb villages in Croatia, Mr Mesic said: "That is just the figment of someone's imagination. I had about as much influence as I had in Lincoln's assassination."

The BBC's Geraldine Coughlan says the defendant has gained some mileage in terms of publicity through his grilling of the witness, but had to be reminded that the purpose of his defence was to challenge the war crimes charges against him.

Damning testimony

On Tuesday, Mr Mesic portrayed Mr Milosevic as a warmonger and as a man without emotion, bent on creating a Greater Serbia at the expense of Yugoslavia and much of its population.

What Milosevic was interested in was a Greater Serbia that would be created on the ruins of the former Yugoslavia

Stipe Mesic

Mr Mesic is the first of a series of high-profile witnesses scheduled to appear in the new, crucial phase of the trial.

He is also the first head of state to testify.

Paradoxically, his appearance comes at a time when the Croatian Government is at loggerheads with the UN tribunal.

It is refusing to hand over a senior Croatian general who has been indicted for war crimes against Serb civilians and wounded soldiers.