"We will work with the Iraqis to develop a way to try him that will stand international scrutiny," Bush told a news conference in which he appeared to leave no room for a UN role. "The Iraqis need to be very much involved."
He said "good riddance" to Saddam, who was captured by US forces on Saturday. But he declined to say whether the ousted Iraqi leader should eventually face the death penalty, which is opposed by US coalition partner Britain.
"I've got my own personal views. This is a brutal dictator. He's a person who killed a lot of people. But my personal views are not important in this matter... It's going to be up to the Iraqis to make those decisions," said Bush, a former governor of Texas, the US state with the most executions, 312, since 1976.
Asked if he had a personal message, Bush said: "Good riddance. The world is better off without you, Mr. Saddam Hussein."
Britain said it would not take part in any trial of Saddam that could lead to his execution. Iran and some human rights activists have said Saddam should be tried by an international court rather than by Iraqis under a US-led occupation.
UN Secretary-General Kofi Annan also expressed his opposition to the death penalty in the case.
"The UN does not support a death penalty. The courts we have set up have not included a death penalty. And so as Secretary-General, as the UN as an organization, I am not going to now turn around and support a death penalty."
Asked whether a UN or international role was crucial, he said: "If the UN is asked to do that, I know that the Security Council will be in a position to make the necessary decisions. For now , this is not a question that is on the table."
Bush warned that US-led occupation forces in Iraq faced continued difficulties and dangers after Saddam's capture, but Iraq was on the right track. He said the capture should convince "fence-sitters" to support the transition under the occupation.
"The terrorists in Iraq remain dangerous. The work of our coalition remains difficult and will require further sacrifice. Yet it should now be clear to all: Iraq is on the path to freedom," he said.
Bush gave no indication the capture would lead to an early withdrawal of US troops and reassured Iraqis the United States would "stay the course."
Bush gave no indication there
would be early withdrawal of troops
He also suggested the capture would do little to help substantiate still-unproven US charges Saddam was developing the unconventional weapons Bush had cited as a major reason for war. Bush said the ousted leader had no credibility.
Saddam had spent more than eight months on the run in the wake of Baghdad's fall at the hands of US-led invasion forces in April.
His capture gave the Bush administration new hopes for an occupation troubled by political unrest and deadly attacks on occupying forces - although car bombings that killed nine Iraqis on Monday made clear the insurgency was continuing.
Former Vermont Gov. Howard Dean, a Democratic presidential candidate who has been one of Bush's most vocal critics on Iraq, said Saddam's capture "has not made America safer," and would not help defeat Usama bin Ladin's al-Qaida network, which Washington blamed for the Sept. 11 attacks and which has been the main target in the US war on global terrorism.
Saddam's capture "has not made America safer" and would not help defeat al-Qaida network
Democratic presidential candidate for US elections
White House spokesman Scott McClellan earlier declined to say whether Saddam was formally being held as a prisoner of war or where he was being held, but said his treatment was in line with international rules.
"He is being treated in accordance with the Geneva conventions and provided protections of a prisoner of war," McClellan told reporters.
In London, British Prime Minister Tony Blair, the main US ally in Iraq, said he was confident Iraqis would be able to mount a fair trial.
"Of course we must make sure that there is a proper and independent and fair process," Blair told parliament. "But I am quite sure that the Iraqis have the capability of doing that."