The Iraqi High Tribunal, funded and advised by the US government, found Saddam guilty of crimes against humanity in the case of 148 Shia civilians who were killed in revenge for an 1982 attempt on the then-Iraqi leader's life.
In a unanimous decision by the tribunal's five judges, Saddam and two co-defendants were sentenced to death by hanging. Another defendant was sentenced to life in prison and three others to 15-year jail terms.
"We had absolutely nothing to do with the actual verdicts or the sentences themselves," said a senior US official close to the tribunal in Baghdad.
The death sentence "was not recommended by the United States, that was solely an Iraqi domestic decision", the official told reporters via video link from the Iraqi capital.
State Department Deputy Spokesman Tom Casey said the death penalty "is something that's been part of Iraqi law for some time".
"We would leave it up to the Iraqi legal system and the special tribunal to determine what the appropriate punishments are," he said.
While the guilty verdict against Saddam was widely welcomed around the world, many US allies, particularly in Europe, criticised the imposition of capital punishment against the former Iraqi president.
British Prime Minister Tony Blair, US President George W. Bush's main ally in the 2003 invasion that toppled the Iraqi leader, said he remained against the death penalty for "Saddam or anybody else".
"The application of the death penalty is unacceptable," added foreign minister Massimo D'Alema of Italy, one of the few other Western governments to contribute troops to the US-led military operations in Iraq.
D'Alema said his government, along with the rest of the European Union, opposed the death penalty in principle and feared that executing Saddam would plunge an already deeply divided Iraq "into a veritable civil war."
Saddam's death sentence was also condemned by the European Union presidency, the Vatican, Russia and human rights groups including Amnesty International and Human Rights Watch.
US officials who have been closely involved with the Saddam trial but who spoke on condition of anonymity because they were not authorised to discuss the matter publicly said the verdict and sentence were in line with international civil rights covenants concerning the treatment of serious crimes.
They rejected suggestions the trial was unfair, or a witch hunt by groups that had been oppressed under Saddam's minority Sunni-led regime.
"When they issued their verdict yesterday, it was a unanimous vote by all five of those judges representing each of Iraq's different ethnic groups," one official said from Baghdad.
"It was up to the court to make determinations of guilt or innocence, we didn't even try to step into that," said another.
Under Iraqi law, sentences of death or life in prison draw an automatic appeal to a nine-member Iraqi appellate court, with a minimum 30-day period for the defence and prosecution to present their positions on the verdict.
There is, however, no deadline for a final ruling by the appeals court.
Saddam was meanwhile due back in court Tuesday for the resumption of a second trial in which he and six senior members of his regime face charges of genocide over the deaths of 182,000 Kurdish civilians in 1988.
Saddam's eventual execution would cut short all legal proceedings against
him, including possible charges linked to Iraq's 1990 invasion of Kuwait, US officials said.

Copyright AFP (Agence France-Presse), 2006