An Iraqi court has resumed hearing the case against Tariq Aziz, one of Saddam Hussein's best-known lieutenants, and seven other former regime officials who face the possible death penalty in the 1992 execution of dozens of merchants.

Aziz, 72, the former deputy prime minister, and ailing co-defendant "Chemical Ali" Hassan al-Majid both leaned on canes as they walked into the courtroom.

Aziz denied the allegations and accused the Shi'ite-led government of seeking revenge against him because of his membership in the former regime.

The trial deals with the execution of 42 merchants accused by Saddam's government of being behind a sharp increase in food prices when the country was under strict UN sanctions.

The merchants were rounded up over two days in July 1992 from Baghdad's wholesale markets and charged with manipulating food supplies to drive up prices at a time when many Iraqis were suffering economically. All 42 were executed hours later after a quick trial.

In outlining the case against the defendants, the chief prosecutor Adnan Ali asked the court "to issue the suitable punishment that will ease the hearts of widows and oppressed ones."

He said all the defendants were charged with crimes against humanity, which means they could be sentenced to death if convicted.

The prosecutor called the merchants' executions "a systematic campaign planned under the cover of darkness" and said the defendants were responsible because they were members of the Revolutionary Command Council, a rubber stamp group that approved the dictator's decisions.

"Those tribunals held their hearings at night and did not allow the defendants to have lawyers or bring any documents that could help their case," he said.

Addressing the judge, Aziz, who had refused to testify against Saddam in previous trials, said the trial was based on personal vendettas and he was proud of his membership in the RCC as well as the former ruling Baath party and other committees under Saddam.

"Concentrating on the membership of the Revolutionary Command Council is meant as revenge," he said. "I know it is a plot of personal revenge."

The trial, the fourth to be held for former regime officials since Saddam was ousted by the 2003 US-led invasion, could represent the last high-profile Saddam-era figure to face prosecution for alleged atrocities. If convicted, they could face the death penalty.

The trial's opening session on April 29 was adjourned because al-Majid was too ill to attend, but the US military, which has custody of the defendants, said Monday that he had been cleared to attend the proceedings.

Al-Majid, who became known as Chemical Ali for chemical attacks against the Kurds in the 1980s, has already been sentenced to death in another case.

Aziz, the only Christian in Saddam's mostly Sunni Muslim coterie, became internationally known as the dictator's defender and a fierce critic of America after Iraq's invasion of Kuwait and the subsequent 1991 Gulf War.

He was later promoted to deputy prime minister and often represented Iraq at the United Nations and other international forums. Just weeks before the US-led invasion, Aziz met with the late Pope John Paul II at the Vatican in a bid to head off the conflict.

Presiding over the trial was judge Raouf Abdul-Rahman, who sentenced Saddam to death in May 2006 for his role in the killing of Shi'ite Muslims in the town of Dujail after an assassination attempt in 1982.

Saddam was hanged the following December while on trial in a second case, stemming from the brutal crackdown on ethnic Kurds in the late 1980s. Chemical Ali was sentenced to death in that case.

A third trial is under way for officials accused of crushing a Shi'ite uprising that followed the 1991 Gulf War.