The chief judge in Saddam Hussein's trial threw the ousted Iraqi leader's intelligence chief out of court during a heated argument after the defense accused the prosecution of trying to buy testimony from a witness.

Former Iraqi President Saddam Hussein scratches his head while listening to the testimony of a defence witness during his trial at the fortified Green Zone in Baghdad May 31, 2006. Defence attorneys for Saddam Hussein accused the prosecution on Wednesday of trying to buy a witness and putting someone on the stand who perjured himself. [Reuters]

The confrontation came Wednesday as defense lawyers stepped up their attempt to undermine the prosecution case, demanding that all its witnesses be re-examined to determine whether they were telling the truth. The lawyers also said all prosecution documents should be reviewed if it turns out that some Shiites the defendants are accused of killing are alive.

Tension in the court grew when one defense witness, testifying from behind a curtain, claimed that chief prosecutor Jaafar al-Moussawi tried to bribe him to testify against Saddam over a crackdown launched against Shiites in the town of Dujail in the 1980s.

The witness said he and his father were arrested in Dujail but released. He said that in 2004 he met al-Moussawi and recounted his story. Al-Moussawi "told me, 'This testimony will not serve the Iraqi people. We want to sentence Saddam to death.' "

"He gave me $500," the witness said. "He told me to say that my father was arrested and killed in detention."

Al-Moussawi accused the defense of making up the testimony and demanded the witness face criminal charges. "There has been a fabricated attack on the prosecution in the past two days," he said. "It must be determined who recruited him to fabricate his testimony."

When chief judge Raouf Abdel-Rahman warned the witness he could be prosecuted if he were lying, Barzan Ibrahim _ Saddam's half-brother and one of his seven co-defendants _ stood and chided the judge, telling him he should "be patient."

"Every session you have a lecture," Abdel-Rahman snapped, shouting at Ibrahim to sit down.

When Ibrahim argued back, Abdel-Rahman shouted, "Get him out of the court!" Three guards then escorted Ibrahim away, one of them holding him by the wrist.

It was the second time that Ibrahim, the former chief of the Mukhabarat intelligence agency, has been thrown out of court during the trial, which began in October.

Saddam and his co-defendants face possible execution by hanging if convicted on crimes against humanity in the Dujail crackdown, which was sparked by a 1982 assassination attempt on the then-Iraqi leader. They are accused of arresting hundreds of Dujail families, torturing and killing women and children and killing 148 Shiites who were sentenced to death.

At the start of Wednesday's session, defense lawyers accused one of the prosecution's first witnesses, Ali al-Haidari, of perjury.

In testimony in December, al-Haidari said he was arrested at age 14 in the Dujail sweep and was tortured with electrical shocks and beatings. He also said there was no shooting attack on Saddam in Dujail on July 8, 1982 _ only celebratory shooting to Saddam's visit.

The defense presented a DVD that showed al-Haidari addressing a 2004 ceremony in Dujail and praising the attack on Saddam as an attempt by "sons of Dujail ... to kill the greatest tyrant in modern history."

"He's ... contradicting his testimony," defense lawyer Ziyad al-Najdawi told the court.

He demanded al-Haidari be investigated for perjury and called for the trial to be halted "to allow for an investigation into the veracity of the other prosecution testimony." Abdel-Rahman did not rule on the defense request.

The court heard five defense witnesses before adjourning until Monday, but the session was dominated by the defense arguments against the credibility of the prosecution's case. On Tuesday, a witness claimed that 23 of the 148 Shiites sentenced to death by Saddam's regime were alive and that he had met some of them in Dujail recently.

Abdel-Rahman ordered an investigation into the claim.

Defense lawyer Mohammed Munib argued Wednesday that in light of the witness' testimony and the perjury claims, the entire discovery process in the case should be redone and all the prosecution witnesses reviewed.

"What we have seen has affected the basic evidence on which the prosecution has depended," Munib said. "This is the heart of the issue, and it can't be avoided or ignored."

He said that if the investigation reveals that some of those sentenced to death are alive, then prosecution documents showing that 148 were killed must have been "fabricated."

The documents are seen as the strongest piece of the prosecution's case. It has presented a wide array of memos and letters from Saddam's presidential office and the Mukhabarat intelligence agency with names of 399 men, women and children imprisoned in the Dujail sweep and the 148 sentenced to death. The documents showed that some of the 148 were children and that others were tortured to death.