Iranian President Mahmoud Ahmadinejad on Sept. 24 defended Holocaust revisionists and raised questions about who carried out the Sept. 11 attacks in a tense showdown at Columbia University, where the school's head introduced the hard-line leader by calling him a "petty and cruel dictator."

Ahmadinejad portrayed himself as an intellectual and argued that his administration respected reason. But he found himself drawn into the type of rhetoric that has alienated American audiences in the past.

He provoked laughter by responding to a question about Iran's execution of homosexuals by saying: "In Iran we don't have homosexuals like in your country ... I don't know who's told you that we have this."