Iranian President Mahmoud Ahmadinejad told the U.N. General Assembly that most people believe the U.S. orchestrated the Sept. 11 terrorist attacks, prompting a walkout by the U.S. and allies and clouding diplomacy efforts by the Obama administration, the Wall Street Journal reported.

In a statement quickly issued after the remarks, the U.S. said that Mr. Ahmadinejad's comments were "as abhorrent and delusional as they are predictable." U.S. officials said the decision to walk out was made after Mr. Ahmadinejad crossed "red lines" established concerning offensive remarks.

Mr. Ahmadinejad described what he said were three theories about the 2001 attacks. The first, that terrorists penetrated U.S. intelligence and defenses. The second: "That some segments within the U.S. government orchestrated the attack to reverse the declining American economy and its grips on the Middle East in order also to save the Zionist regime. The majority of the American people as well as other nations and politicians agree with this view."

The "Zionist regime" is the Iranian president's term for Israel.

The U.S. delegation walked out before Mr. Ahmadinejad's third theory, that the attack was the work of terrorists, supported by the U.S., which "took advantage of the situation." Representatives from a host of allied nations, including the European Union, followed the U.S.

Read more in the Wall Street Journal.