Saddam's six co-defendants include his cousin, Ali Hassan al-Majid, widely known as "Chemical Ali" for his alleged use of poison gas to put down insurrection in the Kurdish heartland in northern Iraq.

They face charges for their role in Operation Anfal, Arabic for "spoils of war," which killed an estimated 100,000 people. Iraqi forces are accused of launching mustard gas and nerve agent attacks in the Anfal campaign.

All seven defendants face charges of war crimes and crimes against humanity for the seven-month onslaught. Saddam and Majid face the additional, graver charge of genocide.

This is the second trial on Saddam and it comes at a time when human rights groups have raised fresh questions about the fairness of the proceedings.

New York-based group Human Rights Watch recently claimed the Iraqi high tribunal was incapable of fairly and effectively trying Saddam and the other defendants because the judges and lawyers did not understand international law.

Saddam also is reportedly likely to challenge the legitimacy of the special tribunal by saying "it was created under U.S. occupation."