The government removed judge Abdullah al-Amiri overnight saying he had abandoned his neutrality for stating last week that Saddam was "not a dictator." International legal rights groups said the move rode roughshod over the tribunal.

"Take him out of the courtroom," the new judge, Mohammed al -Ureybi, told guards after Saddam launched a tirade and refused to sit down. Saddam accused the new judge of being the son of a government spy before the U.S.-led invasion in 2003.

"Your father was a security agent!" Saddam said. "I knew him. He had an operation here," he added, gesturing at his own abdomen.

"I challenge you to prove that to the public." the judge said dismissively as Saddam was being escorted out.

The court is trying Saddam, his cousin Ali Hassan al-Majeed, known as "Chemical Ali," and five others for war crimes and crimes against humanity.

Wadood Fawzi, a lawyer for Saddam and Majeed, said government pressure was keeping counsel from performing its job.

"The sacking of the judge confirmed our fears that this court lacks the conditions to hold a fair trial," Fawzi said.

"If you wish to leave, that's fine. Then go," the judge said. The defence lawyers filed out of the courtroom.

Government spokesman Ali al-Dabbagh said on Tuesday the decision to sack Amiri was made by the cabinet in accordance with the Iraqi High Criminal Court Law, which allows the government to transfer judges from the court for "any reason."

But legal rights groups said the decision by Shi'ite Prime Minister Nuri al-Maliki to replace the judge a month after the case opened hurt its legitimacy in the eyes of Iraqis.