Saddam Hussein's cousin, known as "Chemical Ali," and another close aide to the dictator who represented him abroad appeared in court Sunday accused of orchestrating the bloody repression of Shiite riots after the 1999 assassination of the father of anti-U.S. cleric Muqtada al-Sadr.

It was the fifth trial of top Saddam-era figures and the second to include Tariq Aziz, who became internationally known as the dictator's defender and a fierce American critic after Iraq's invasion of Kuwait and the subsequent 1991 Gulf War.

Grand Ayatollah Mohammed Sadiq al-Sadr, one of the most powerful Shiite clerics in Iraq in the 1990s, was killed with two of his sons in an ambush on Feb. 20, 1999, in the holy city of Najaf. His followers said Saddam's agents were to blame.

The next day, angry loyalists rioted near a mosque in Baghdad's main Shiite district - then called Saddam City but later renamed Sadr City after the elder cleric - blockading roads and ordering shop owners to shutter up in mourning. Iraqi policemen trying to break up the protest were beaten and police cars destroyed.

Saddam's paramilitary Fedayeen militia opened fire on the protesters and a curfew was imposed while the whole district was sealed off until the next day.

Citing documents from Saddam's now-outlawed ruling Baath Party, chief prosecutor Munqith al-Faroon on Sunday said Saddam's security forces opened fire on the Sadr City crowd, killing 16 people. He said 14 others were killed in a similar crackdown in the Shiite southern city of Amarah.

Families were then ordered not to hold public funerals for those killed, al-Faroon said, citing Baath Party documents.

The documents acknowledge that some people were shot by mistake because they were near the riots, and listed the names of some victims along with their political backgrounds, according to al-Faroon.

Aziz claimed the defendants had not been granted sufficient time to discuss the case with their lawyers. "We want real meetings with our lawyers," he told the court.

Another defendant who had been interior minister at the time, Mohammed Zumam, insisted he was innocent. "I have nothing to do with this case," he said.

Aziz, the only Christian among Saddam's inner circle, was for years one of the most visible leaders of the ousted regime. Among his 15 co-defendants, who were all present in court Sunday, was Ali Hassan al-Majid, known by the nickname of "Chemical Ali" for ordering poison gas attacks against Iraq's Kurdish minority in the 1980s.

Formal charges were to be filed later in the trial, but a court official, speaking on condition of anonymity for lack of authorization to release the information, said the charges were expected to include crimes against humanity, which would carry the death penalty.

Aziz also faces charges in another trial under way for officials accused in the 1992 execution of dozens of merchants accused of manipulating food supplies to drive up prices during hard economic times under U.N. sanctions.

Al-Majid has already been sentenced to death for his role in the crackdown against the Kurds, but the execution has been delayed by legal wrangling. He also has been accused in an ongoing trial over the deadly crushing of a Shiite uprising that followed the 1991 Gulf War.

Saddam was sentenced to death in May 2006 for his role in the killing of Shiite Muslims in the town of Dujail after an assassination attempt against him there in 1982. Saddam was hanged the following December.