"It reconfirms what we've been saying about the regime in Iran. It underscores the concerns we have about Iran's nuclear intentions," spokesman Scott McClellan told reporters.

At a conference in Tehran entitled "The World Without Zionism," the hardline Iranian leader declared that "the establishment of the Zionist regime was a move by the world oppressor against the Islamic world."

"As the imam said, Israel must be wiped off the map," Ahmadinejad said, referring to a slogan which Iran's revolutionary leader Ayatollah Ruhollah Khomeini used before his death in 1989.

Ahmadinejad's comments marked the first time in years that such a high-ranking Iranian official has openly called for Israel's eradication, even though such slogans are still regularly used at regime rallies.

Washington has accused Tehran of using a civilian nuclear program as cover for efforts to develop atomic weapons. Iran has denied the allegation.

Britain, France and Germany have held talks with Iran, offering incentives in exchange for a cessation of work on nuclear fuel, but the negotiations broke down in August when Tehran rejected their offer.

Iran also ended a freeze on fuel cycle work by resuming uranium conversion -- a first step in making enriched uranium, which can be fuel for nuclear power reactors but also atom bomb material.

The 35-nation IAEA board passed a resolution in September finding Iran to be in non-compliance with the nuclear Non-Proliferation Treaty (NPT) -- paving the way for the matter to be referred to the UN Security Council.