Baghdad: Former commanders of Saddam Hussain's military went on trial in Baghdad on Tuesday for their role in crushing a Shiite rebellion in southern Iraq at the end of the 1991 Gulf War in which tens of thousands were killed.

Standing alongside the military officers were Saddam's former defence minister at the time and his personal secretary.

The most high profile of the 15 defendants is Saddam's feared cousin, Ali Hassan Al Majeed, known as "Chemical Ali".

The chief judge, Mohammad Oraibi Al Khalifa, told the men they were charged with crimes against humanity. The court has said the charges are "for engaging in widespread or systematic attacks against a civilian population".

The rebellion, and a simultaneous one in Kurdish areas in northern Iraq, erupted spontaneously in early March 1991 after a US-led coalition routed Saddam's army in Kuwait. Rebels seized control of many towns in the south.

The rebels expected US forces to come to their aid, especially since then US President George Bush senior had called on the Iraqi people and the military to oust Saddam.

But Bush and his coalition partners held their troops in check and Saddam was given a free hand to launch a counterattack with tanks and helicopters.

Tens of thousands are estimated to have been killed in the crackdown, either by the pursuing security forces or in prison. Prosecutors in the case have put the death toll at 100,000.

Bush has since argued that, while he hoped a popular revolt would topple Saddam, he did not want the Iraqi state to break up and feared the collapse of the multinational coalition, including Arab states, that he had assembled.

Three of the 15 accused, including Al Majeed, were sentenced to death in an earlier Anfal trial, which dealt with a military campaign against Kurds in northern Iraq in 1988 in which tens of thousands of people were also killed.

The five convicted in the Anfal case are appealing against their sentences. If Al Majeed and the two others sentenced to death lose their appeal they could be executed before the latest trial is completed.

The court will hear about 90 witnesses, and audio tapes and after-action reports. Unlike the Dujail or Anfal trials, Tuesday's hearing was not televised.