Saddam Hussein's cousin known as "Chemical Ali" and 14 others faced charges of crimes against humanity for the brutal crushing of a Shiite uprising after the 1991 Gulf War Tuesday as Iraq's third trial against former regime officials began with three of the defendants already sentenced to death in another case.

The Iraqi High Tribunal said the defendants are charged with engaging in widespread or systematic attacks against the civilian population, and the evidence would include testimony from about 90 victims and witnesses.

Saddam's cousin and the former defense minister Ali Hassan al-Majid, who gained the nickname "Chemical Ali" after chemical attacks on Kurdish towns during the so-called Anfal campaign, entered the courtroom wearing his traditional white Arab robe and a red headdress.

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The charges stem from the aftermath of the 1991 Gulf War, in which the U.S. drove Saddam's forces from Kuwait.

Shiites in the south and Kurds in the north sought to take advantage of the defeat, launching uprisings and seizing control of 14 of the country's 18 provinces. U.S. troops created a safe haven for the Kurds in three northern provinces, preventing Saddam from attacking. But the late dictator's troops marched into the predominantly Shiite south and crushed the uprising, killing tens of thousands of people.

It will be the third trial of former regime officials after the Dujail case, in which Saddam and three others were hanged for the 1982 killings of 148 Shiites, and the trial of those accused of killing of more than 100,000 Kurds in a 1980s military campaign.

Al-Majid was sentenced to death in that case but will stand trial in the Shiite uprising case pending his appeal, the court said.

Two others sentenced to death for the Kurdish killings — Sultan Hashim Ahmad al-Tai, the former defense minister who led the Iraqi delegation at the cease-fire talks that ended the 1991 Gulf War, and Hussein Rashid Mohammed, a former deputy director of operations for the Iraqi armed forces — also will face trial in the latest case, he said.

Another high-profile defendant will be Saddam's trusted personal secretary and bodyguard Abed Hameed Hmoud, al-Moussawi said.

The chief judge was Mohammed Oreibi al-Khalifa, who also presided over the Anfal trial, and the chief prosecutor Mahdi Abdul-Amir.

Officials in Saddam's regime still face trials for their alleged role in other crimes. These crimes include the slaying of members of political and religious parties, the 1990 invasion of Kuwait, the forced emigration of thousands of Shiite Kurds from northern Iraq into Iran, the execution of 8,000 members of the Kurdish Barzani tribe, and the destruction of the marshes in southern Iraq.

Complete coverage is available in FOXNews.com's Iraq Center.