Former senior Iraqi official Ali Hassan al-Majid - widely known as Chemical Ali - has been questioned by Iraqi judges in a pre-trial hearing.
'Chemical' Ali got his nickname for his alleged role in gassing Kurds
The key Saddam aide is accused of some of the worst crimes committed by the regime, including gassing Iraqi Kurds.
He appeared in Baghdad along with Gen Sultan Hashim Ahmed, Saddam Hussein's last defence minister, a judge said.
The hearing marks a new stage in the trial process against the former Iraqi leader and 11 top officials.
The head of a panel of investigating judges set up by the special Iraqi tribunal to try Saddam Hussein and his former aides said Saturday's hearing - a normal part of the judicial process - did not mean a trial was imminent.
Last Tuesday, interim Prime Minister Iyad Allawi suggested the trials of what he called "the symbols of Saddam Hussein's old regime" could begin as early as this week.
Film released after the hearings showed top investigating Raad al-Juhiy interviewing both men, separately, at a desk in a large, bare room.
Both arrived handcuffed and flanked by Iraqi policemen, Reuters news agency reported.
Looking well and supported on a walking stick, Mr Majid, Saddam Hussein's cousin, smiled to the guards, Reuters said.
"Ali Hassan al-Majid and Sultan Hashim have been interrogated and their lawyers attended the investigative hearing," judge Juhiy said.
"Ali Hasan al-Majid has been interrogated about the charges against him. We're in the investigation phase. Ali Hasan al-Majid, like other defendants, appeared before the investigative judge."
Mr Jouhiy said this was not formally the start of trial but merely a preliminary stage of the legal process.
"We should make a distinction between the trial and the investigation," he said.
'CHEMICAL' ALI: FACTS
Saddam Hussein's paternal cousin
Best known over 1987 gassing of Kurds in north Iraq
Becomes governor of Kuwait after 1990 annexation
Served as interior and defence minister
Killed his two nephews who defected to Jordan, alongside their father (his own brother) in 1995
"Hurrying will not help this case," he said.
Observers say the timing of Mr Allawi's surprise announcement last Tuesday that trials could start as early as next week could be linked to the Iraqi elections planned for 30 January.
But the Associated Press news agency quoted an Iraqi government spokesman as saying Mr Allawi had not been referring to the full trials.
"This [the Saturday hearings] is what the doctor [Allawi] announced," said Thair al-Naqeeb.
Saddam Hussein had his first meeting with a member of his defence team on Thursday, more than a year after being captured.
There is no indication of when he will face trial. He and 11 top regime figures are in US custody.
Lawyers representing members of the former leadership have said their clients will not recognise the legitimacy of any courts established under US occupation.
International legal experts have also voiced concern that the trials are being rushed and that defendants will not get a fair hearing.