Saddam Hussein's death sentence was celebrated by some as justice deserved but denounced by others as a political ploy before critical US mid-term congressional elections.
Worldwide, the range of reactions about the fairness of the tribunal that ordered Saddam to hang reflected new geopolitical fault lines drawn after the US decision to invade Iraq in 2003 and depose its dictator.
The European Union welcomed the verdict but said Saddam should not be put to death.
At the Vatican, Cardinal Renato Martino, Pope Benedict XVI's top prelate for justice issues, called the sentence a throwback to "eye for an eye" vengeance.
Thai Muslim cleric Vitaya Wisethrat
Islamic leaders warned that executing Saddam could inflame those who reviled the US, undermining President Bush's policy in the Middle East and inspiring terrorists.
"The hanging of Saddam Hussein will turn to hell for the Americans," said Vitaya Wisethrat, a respected Muslim cleric in Thailand, which has its own Islamic uprising in the country's south.
"Maybe Bush will use this case to tell the voters that Saddam is dead and that the Americans are safe. But actually the American people will be in more danger with the death of Saddam."
Praising the Iraqi judiciary for its independence, the White House denied arranging for the verdict to be announced just two days before pivotal elections in which Democrats are fighting for control of Congress.
"The idea is preposterous," said Tony Snow, Mr Bush's spokesman.
Intervening militarily was "a grave error", said Spanish prime minister Jose Luis Rodriguez Zapatero, whose country withdrew its troops from Iraq, saying that conditions there had worsened since the US-led invasion.
Although some voiced doubts that Saddam would actually be hanged, the International Federation for Human Rights denounced the death sentence, warning that it "will generate more violence and deepen the cycle of killing for revenge in Iraq".
The Council of Europe called it "futile and wrong" to execute Saddam, while Amnesty International questioned the fairness of the trial.
Louise Arbour, the UN high commissioner for human rights, urged Iraq to ensure a fair appeals process and to refrain from executing Saddam even if the sentence was upheld.
But key US allies - including Britain and Australia - welcomed yesterday's verdict. "Appalling crimes were committed by Saddam Hussein's regime. It is right that those accused of such crimes against the Iraqi people should face Iraqi justice," British Foreign Secretary Margaret Beckett said.
"The whole process of the trial is a sign of democratic hope and I believe the world should see it as such," Australian prime minister John Howard said.
In the Arab world, some Muslims saw the sentence as divine retribution, but others decried it as a farce. "Saddam is being judged by traitors, Americans and Iranians, and those who came on the backs of American tanks," said Mahmoud al-Saifi of the Arab Liberation Front.
Iran, which fought an eight-year war against Saddam's Iraq and is a bitter opponent of the United States, praised the death sentence and said it hoped that Saddam - denounced by one politician as "a vampire" - would be tried for other crimes.
AP