Saddam Hussein made a defiant start to the latest day of his trial in Baghdad having earlier threatened to boycott proceedings.
He entered the courtroom shouting 'Down with Bush'.
The former Iraqi dictator had refused to attend previous sessions in protest at the new judge appointed to preside over the trial.
He and his fellow defendants had also refused to co-operate with court-appointed lawyers after their own team walked out in protest.
Saddam complained to the court that he had been forced to attend the latest proceedings.
He shouted: "Down with the agents. Down with Bush. Long live the nation," as he entered.
He looked haggard and wore a blue galabeya - a traditional Arab robe -and a black jacket, a contrast to the tailored black suits he has worn to past sesssions.
Fellow defendant Barzan Ibrahim scuffled with guards and shouted angrily when he was brought in and then sat on the floor with his back to the judge.
Barzan Ibrahim scuffled with guards Raouf Abdel-Rahman was appointed as judge in place of Rizgar Amin and has adopted a more hardline approach to the defendants.
The defence claims Mr Abdel-Rahman is unfit to try the case because he was sentenced to life in absentia in the 1970s for anti-state activity
Saddam and his seven co-accused face charges over their alleged role in the 1982 massacre of 143 Shi'ites north of Baghdad and have all pleaded not guilty.
When proceedings started, former Saddam aide Ahmed Hussein Khudayer al-Samarrai was called as a witness.
Prosecutors are trying to show a direct link between Saddam and the events in the town of Dujail.
But Mr al Samarrai said he could not remember anything and told the court: "I am not fit to be a witness in this case," bringing a smile from Saddam.
He also claimed he had been forced to appear at the trial, as did Hassan al-Obeidi, a former intelligence director.
After three hours, the trial was adjourned until Tuesday.