"Today is an important mile stone for Iraq as the country takes another major step forward in the building of free society based on the rule of law," Zalmay Khalilzad said in a statement.

"A former dictator feared by millions, who killed his own citizens without mercy or justice, who waged wars against neighboring countries, has been brought to trial in his own country -- held accountable in a court of law with ordinary citizens bearing witness," the statement said.

However, Khalilzad anticipated that Iraqis will face difficult days in the coming weeks.

"Although the Iraqi people will face difficult days in the coming weeks, closing the book of Saddam and his regime is an opportunity to unite and build better future," the statement said.

Saddam and two codefendants were sentenced to death by hanging after the Iraqi High Tribunal found them guilty of crimes against humanity.

The former vice president Taha Yassin Ramadan was sentenced toa life prison, while other three Baath party local officials from Dujail received 15 years each.