BAGHDAD, Iraq — Saddam Hussein and four other defendants refused to attend their trial today, and their defense attorneys boycotted the proceedings, demanding the removal of the chief judge they claim is biased against the former Iraqi leader.

Chief judge Raouf Abdel-Rahman pressed ahead with court-appointed defense lawyers and only three defendants present.

He first held a half-hour closed session today, barring media from the courtroom. It was not clear whether Saddam was brought in for the closed hearing, and court officials did not say what took place.

Saddam and four other co-defendants were not present when the session was opened to the public.

Chief prosecutor Jaafar al-Moussawi asked the judge to force all defendants to attend. Abdel-Rahman ruled that the court proceedings would continue but that the five-judge panel would consider the request in future hearings.

Abdel-Rahman then turned to the three remaining defendants, surrounded by empty chairs in the pen set up in front of the bench.

"Because your lawyers stayed away and dropped your cases, the court has decided to appoint the lawyers who are in the courtroom," he told them.

The court then heard the testimony of a prosecution witness, a woman whose identity was withheld and who spoke from behind a beige curtain.

The boycott by the defendants and lawyers is the latest problem to plague Saddam's tumultuous trial, which in its previous eight sessions saw numerous delays, a shake-up among the judges, and outbursts by Saddam and Barzan Ibrahim, his half brother and former intelligence chief.

Abdel-Rahman was brought in as chief judge Sunday to replace a predecessor who resigned amid criticism he was not doing enough to control the proceedings.