Annan said the Bush administration would get more support, such for its activities in Iraq and elsewhere if it built alliances patiently.

"I sense a widespread international acceptance of American leadership," he said, according to remarks prepared for a speech in Los Angeles for the 50th anniversary of the World Affairs Council.

"But I also sense that its leadership will be more admired than resented, and indeed that it will be most effective, when it is exercised within a multilateral framework, when it is based on dialogue and the patient building of alliances through diplomacy, and when it is aimed at strengthening the rule of law in international affairs," Annan said.

The Bush administration has been has been criticised by allies for its rejection of the Kyoto global climate treaty, the International Criminal Court and the lack of a legal framework for suspects held in Guantanamo Bay, among other issues.

Tracing the key US role in founding the United Nations 58 years ago, Annan said that the world had rarely been more united than in the aftermath of the Sept. 11, 2001 attacks on New York and Washington.

At that time, he said, nearly all governments understood that the best way -- and perhaps the only way -- was to confront terrorism through collective action.