President Bush, concluding a three-day summit meeting with key world leaders, said today he was encouraged by the prospect of more international help for Iraq, but he said Iraqis ultimately would have to take responsibility for their own security.

In a press conference in Savannah, Ga., as the Group of Eight summit in Sea Island drew to a close, a generally upbeat Bush called the conference a success and said policy differences over Iraq with allies such as France and Germany were in the past.

Bush made the remarks before flying back to Washington to pay his respects to the late president Ronald Reagan at the Capitol Rotunda, where Reagan's body is lying in state until Friday morning. Bush then planned to offer condolences to former first lady Nancy Reagan and her family at Blair House in Washington.

Asked about other nations' reluctance to offer more debt relief or troops for Iraq, Bush said it was too early to draw conclusions, noting that a new U.N. Security Council resolution on Iraq was approved only this week and that a new interim Iraqi government will not receive political power from the U.S.-led occupation authority in the country until June 30.

In any case, he said, "There will be an Iraqi face on the security of Iraq. The Iraqis will secure their own country, and we're there to help them do so."

Bush said, "The response here at the G8 has been very encouraging." He said the Group of Eight leaders -- representing Britain, France, Germany, Japan, Russia, Italy and Canada, as well as the United States -- want to wait for any requests from the Iraqi government before deciding on further assistance.

Bush said he "suggested to the leaders of the G8 that we listen to the needs of the Iraqi leadership, and if they ask for more training, for example, a good organization to provide that training would be NATO."

But he added, "I don't expect more troops from NATO to be offered up. That's an unrealistic expectation." What he is suggesting, Bush said, is that NATO help to train Iraqi security forces at the request of the Iraqi government.

The subject was discussed earlier today at a meeting between Bush and President Jacques Chirac of France, officials said. Chirac indicated he was dubious about a NATO role in Iraq, but did not rule anything out, a senior Bush administration official told reporters. The issue is expected to be discussed further at a NATO summit in Istanbul later this month.

In the press conference, Bush said past policy differences with some of the leaders have not affected his personal relationships with them.

"We're united by common values," Bush said. "It's to be expected that nations don't agree on every issue." He added that he admired leaders with strong opinions.

"We've got too much to do in a world beset by terror, poverty and disease to allow a policy difference to prevent us from working together," Bush said. "That's why these G8 summits are meaningful and worthwhile."

Questioned about a Justice Department memo that suggested that the torture of al Qaeda terrorist suspects might be legally defensible, Bush said he could not recall having seen the memo. But he said he had issued an authorization stating that "anything we did would conform to U.S. law and would be consistent with international treaty obligations."

Bush brushed aside further questions on whether he would authorize torture if he knew a captive had information that could prevent a major terrorist attack, and on the underlying moral issue of whether torture was ever justified.

"The instructions went out to our people to adhere to the law," he said. "That ought to comfort you."

Bush also was dismissive when asked what he could tell the American people about when U.S. troops would come home from Iraq in large numbers.

"When the job is done," he said.

In opening remarks, Bush stressed that the Group of Eight nations "are committed to the success of Iraq's government, the defeat of its enemies and the future of Iraq as a free and democratic state." And he repeated his oft-stated view that a democratic Iraq would be an agent for reform in the Middle East.

"The spread of freedom throughout the broader Middle East is the imperative of our age," he said.