The United States joined key allies Wednesday in condemning new remarks by Iranian President Mahmoud Ahmadinejad, who called the Nazi extermination campaign against European Jews a myth. The State Department said the Ahmadinejad remarks are isolating Iranians from the rest of the international community.

The Bush administration is calling the Iranian president's latest remarks outrageous and says they, among other things, underline why his country must not develop nuclear weapons.

Mahmoud Ahmadinejad (file photo)

President Ahmadinejad, an Islamic hardliner who took office in August, startled U.S. officials the following month with a defiant United Nations address on his country's nuclear program, and later drew worldwide condemnation for remarks calling for Israel to be wiped off the map.

At a news briefing, State Department Spokesman Sean McCormack said Mr. Ahmadinejad's assertion Wednesday that the World War II Jewish Holocaust is a "myth" was reprehensible and another sign that Iran is "headed off in a direction 180 degrees from the rest of the world."

Mr. McCormack said it is not the Iranian people who are driving the country away from the global community, but rather the clerical leadership in Tehran.

"The Iranian people are a great people," he said.  "They have a rich culture. They have a rich history. They have a lot to offer the rest of the world. But through the actions and the statements of their government, what is happening is that they are isolating themselves as a country and a people. It's not the Iranian people who are doing that. It's their leadership and the unelected leadership that really controls the power in Iran."

Mr. McCormack said President Ahmadinejad began "digging himself a diplomatic hole" with his U.N. General Assembly speech and has kept on digging.

His White House counterpart, Scott McClellan, said all responsible world leaders understand how outrageous such comments are, and that they underscore how important it is that the world community work together to keep Iran from developing nuclear weapons.

A senior official who spoke to reporters here said the incendiary comments about Israel and the Jews can no longer be dismissed as an accident or a slip of the tongue, but have to be seen as what Mr. Ahmadinejad and others in his government really believe, which the official said "is all the more disturbing."

The Bush administration has long held that Iran is secretly developing atomic weapons under cover of its nominally peaceful nuclear program, and is supporting terrorism and radical Palestinian factions that are trying block Middle East peace efforts.

In a Washington address Tuesday, Secretary of State Condoleezza Rice said Iran is meddling in Iraq and supporting violence there, and poses a problem to a democratizing Middle East that she said the world community "will have to find a way to deal with."