A grey-bearded 69-year-old Saddam was led into the Iraqi High Tribunal in his dark business suit, along with six co-defendants accused of leading the savage 1987-88 Anfal campaign against Iraq's Kurdish minority.

The strongman, who maintained his claim to be "President of the Republic of Iraq", refused to enter a plea and the judge ordered that one of "innocent" be entered in the record.

Saddam's cousin Ali Hassan al-Majid, who became notorious as "Chemical Ali", also refused to plead and was recorded as pleading innocent.

The start of the case was marked in the Kurdish region of northern Iraq by five minutes of silence on behalf of Anfal's victims, while Iraqis across the war-torn country tuned in to television coverage of the historic trial.

"I urge you to listen carefully to the details of these events... It is difficult to fathom the barbarity of such acts," chief prosecutor Munqith al-Faroon said as he began to lay out his case.

"Thousands of people were displaced across Iraq. Infants were looking for fathers, while families were looking for youngsters. But there was no hope. Women were transferred to detention centres, raped and tortured," he said.

Prosecutors showed the court photographs of mass graves -- including one in which the body of an infant child still sucking a milk bottle was buried next to his mother -- and detailed the eight stages of the Anfal campaign.

Beginning on February 22, 1988, the Iraqi airforce began firing chemical weapons into the Juwaid Valley outside the northern city of Sulaimaniyah. This was followed up with an artillery barrage, the court heard.

Over the next eight months troops were sent into Kurdish regions, repeatedly using poison gas, as whole villages were isolated and attacked, he said.

"Women, children were transferred to detention centres made in advance. Detainees suffered harshly. Camps had no basic services. Detainees were exposed to torture, insults and non-potable water," Faroon said.

"Those who died were buried outside the camps by the detainees and later animals were set free to dig up those graves, mostly in the Samawa desert.

"Women were put through psychological torture. Their infant babies were separated from them. The babies and the mothers were allowed to cry. Young men were raped by guards and officials," he told the court.

The defence is expected to argue that Anfal was a legitimate counter-insurgency operation against Kurdish separatist guerrillas who sympathised with the Iranian side in the Iran-Iraq war from 1980-1988.

Saddam's defence counsel, Khalil al-Dulaimi, declared the court illegal, arguing that an administration set up under US tutelage had no right to try Iraqis, an argument used in Saddam's first trial without success.

Presiding over the trial was chief judge Abdallah al-Ameri, a Shia Arab with 25 years on the bench, supported by four colleagues in a process which prosecutors hope will last for only four months.

Saddam had clashed with the judge when asked to identify himself, accusing him of working on behalf of the US forces operating in Iraq.

"You are here in the name of the occupier not in the name of Iraq. My name is known to Iraqis and to the world," Saddam declared, before introducing himself as "Saddam Hussein, the President of the Republic of Iraq".

Al-Ameri also shouted at Chemical Ali to sit down after he stood up in deference to Saddam as his former boss was led back into court after a break.

Saddam had previously been tried on a charge that he ordered the execution of 148 Shia civilians from the town of Dujail after a failed assassination attempt against the then-president.

Proceedings in the Anfal trial could be interrupted by the verdict in the Dujail case, as judges are due to announce their verdict on October 16. If Saddam is found guilty, he could be given the death penalty.

If so, he would have an automatic right of appeal, but if he loses he could face the hangman before the Anfal trial is complete.

The case against Saddam's co-defendants, former senior security officials in his regime, would continue however, as prosecutors seek to make the events of 1988 a matter of legal record and heal some of Iraq's wounds.

Standing trial alongside Saddam and Majid are: Saber al-Duri, Saddam's director of military intelligence; Taher al-Ani, former governor of Mosul; Sultan Hashem al-Tai, commander of "Task Force Anfal"; Hussein Rashid al-Tikriti, deputy chief of military operations; and Farhan al-Juburi, a senior intelligence officer.