Saddam made repeated outbursts during the trial and called for resistance to the US-led occupation which led the chief judge Rauf Abdel Rahman to close the session.
Judge Abdel Rahman cut Saddam off after about 20 minutes, declaring that his statements were political and ordering the galleries cleared and television transmission stopped.
The remainder of Saddam's testimony was heard in closed session before the judge adjourned the case to April 5.
The Iraqi High Tribunal is trying Saddam and seven co-defendants, including former top regime officials, over a massacre of Shiites in the 1980s. They have all pleaded not guilty but face execution if convicted.
Call for unity
"I call on the people to start resisting the invaders instead of killing each other," Saddam said, describing himself as the country's legitimate president.
"My people will never accept the occupation, it is my people who elected me in a referendum and who trusted me to lead them to safe harbour and I say to my people I remain faithful to them despite the injustices of which I am a victim," Saddam said, reading from a text written in a yellow notebook.
He also called those who destroy mosques "criminals", a reference to the outbreak in sectarian violence that has rocked the country since the destruction of a Shiite shrine on February 22.
Saddam took the stand wearing his trademark tailored dark suit without a tie and reading glasses.
"I speak as president of the republic and the commander in chief of the armed forces," he said.
"Your rule has ended, now you are a defendant in a criminal case," Abdel Rahman told him. "This is a criminal court, we are not interested in politics."
Saddam retorted: "As far as I am concerned, I take my responsibilities to the people seriously, until such a time as the people choose someone else to represent them.
Saddam later told the judge "if it wasn't for America, neither you nor your father could drag me here."
The judge ordered him several times to confine his comments to the specific of the case arising out of the killing of 148 Shiites from the village of Dujail after Saddam escaped assassination there in 1982.
When Saddam embarked on another speech about the "criminals who had invaded the country on the pretext of finding weapons of mass destruction" the judge ordered the session closed.
Barzan denial
Saddam’s appearance followed lengthy morning testimony by his half brother and feared former secret police chief Barzan al-Tikriti.
Barzan denied involvement in mass reprisals ordered against Dujail after the assassination attempt.
"I arrested no one, it was the security services that were in charge" of operations in Dujail, he said.
"I can assure you I have no responsibility in this matter. It was handled by the former head of security who has since died. Just show me one document proving that I ordered an arrest or the destruction of someone's farm."
Wearing traditional Arab dress Barzan appeared alone, wearing glasses and reading from a statement.
The trial, which opened in October, has reached its mid-way point.
The three-judge panel is now expected to draft specific charges against each defendant before resuming with the prosecution and defence arguments. All defendants could be hanged if found guilty.
Case rejected
Meanwhile, the European Court of Human Rights has rejected a case brought by Saddam against 21 European countries that were part of the coalition that invaded his country in 2003.
Saddam's lawyers said his capture, detention and trial were a violation of several articles of the European Convention on Human Rights.
But the court decided that he was not under the jurisdiction of any European state at the time, so the plea was inadmissible.