Sept. 24 (Bloomberg) -- Iranian President Mahmoud Ahmadinejad took the podium at Columbia University to defend his doubts about the Holocaust and dispute allegations that Iranian dissidents are mistreated after coming under verbal attack from his host.

University president Lee Bollinger, chastised by protesters and politicians who said Ahmadinejad should never have been invited, opened the 90-minute event in New York by calling his guest a ``petty and cruel dictator.'' Bollinger challenged Ahmadinejad to speak about the mass murder of Jews during World War II, Iranian support for terrorist groups and his country's nuclear aims.

Ahmadinejad complained that Bollinger's remarks were an inhospitable insult and then gave a wide-ranging defense of his outlook that began with 30 minutes of quotations from the Koran on the value of science and education. He said Palestinians were paying for the Holocaust with the violence in the Middle East, and that the ``historical event'' required more study.

The Iranian leader, 50, who is in New York to speak tomorrow to the United Nations General Assembly, said little about the nuclear program that has put him at odds with the U.S. and European governments. Surprises came when he turned to social issues: he provoked gasps and laughter in the audience by asserting that there were no gays in his homeland.

Gays, Women

``In Iran, we don't have homosexuals, like in your country,'' Ahmadinejad said in response to a question about why homosexuals face severe punishments. ``In Iran, we do not have this phenomenon. I don't know who's told you that we have it.''

An English major at Columbia, Carla Baricz, 20, said ``everyone knew he wasn't telling the truth'' about homosexuals in Iran. ``I came with an open mind, and I'm leaving not quite certain where he stands, which is probably just how he wants it,'' she said.

Ahmadinejad said women in Iran ``enjoy the highest levels of freedom,'' when watchdog groups such as New York-based Human Rights Watch have accused Iranian authorities of jailing women's rights activists.

Ahmadinejad defended Iran's nuclear program, saying it is for peaceful purposes only. He spoke as members of the Security Council and Germany are discussing whether to impose another set of sanctions on the Middle East's second-largest oil producer for refusing to curb uranium enrichment, a process the U.S. and its partners say Iran is pursuing to create a nuclear weapon.

Free Speech

Thousands of protesters demonstrated outside the auditorium where Ahmadinejad, who once sponsored a conference that questioned the existence of the Holocaust, was speaking. Bollinger defended the invitation, saying free-speech principles in the U.S. require open debate.

``Our responsibility today is to listen and ask questions in an atmosphere of civility and restraint,'' Bollinger said. Addressing opponents of the invitation, he said, ``I understand your perspective and respect it as reasonable. The scope of free speech and academic freedom should always be open to debate.''

Undersecretary of State Nicholas Burns, in an interview, said Ahmadinejad's appearance highlighted the openness of U.S. society and said he wished the Iranian people would see how Americans react to their president.

``They will not see the anger that many people have against him,'' Burns said. ``He is a denier of the Holocaust.''

Bollinger, in opening remarks, challenged Ahmadinejad on the recent detentions of Iranian-American scholars including Columbia alumnus Kian Tajbakhsh and on his comments that the Holocaust is fabricated and Israel should cease to exist.

Dictator

``Mr. President, you exhibit all the signs of a petty and cruel dictator,'' Bollinger said as Ahmadinejad sat nearby on the stage. ``And so I ask you, why have women, members of the Ba'hai faith, homosexuals and so many of our colleagues become targets of persecution in your country?''

Bollinger asked Ahmadinejad to allow Tajbakhsh, who was released on bail after more than four months in Tehran's Evin prison, to leave Iran whenever he wants. Bollinger also announced that the university is inviting Tajbakhsh, who works with George Soros's Open Society Institute, to teach as a visiting scholar.

Bollinger's opening remarks were ``an insult to the information and the knowledge of the audience here,'' Ahmadinejad said at the beginning of his speech.

John Coatsworth, the acting dean of Columbia's School of International and Public Affairs, who moderated the discussion, said he was pleased with the outcome.

`Tough Questions'

``They sent up very tough questions, and they expected me to make sure that they were answered. I think that many of them were not answered, and I think the Iranian president missed an enormous opportunity. But we achieved our educational objective which was to present to our students what they will find in the world outside of Columbia when they graduate,'' Coatsworth said in an interview after Ahmadinejad's remarks.

Ahmadinejad said more research is needed on the Holocaust, calling it ``a historical event that has become the root, the cause of many heavy catastrophes in the region in this time and age.''

He said his main point was that academics should be allowed to continue their inquiries as they do in other fields.

``I am not saying that it didn't happen at all,'' he said. ``This is not that judgment that I am passing here.

``My first question was if, given that the Holocaust is a present reality of our time, a history that occurred, why is there not sufficient research that can approach the topic from different perspectives?'' Ahmadinejad said.

Pay a Penalty

Palestinians had no part in World War II and shouldn't have to pay a penalty with displacement and attacks, Ahmadinejad said, referring to the conflict with Israel.

``You know quite well that Palestine is an old wound, as old as 60 years,'' Ahmadinejad said. ``For 60 years, these people are displaced. For 60 years, these people are being killed.''

Ahmadinejad condemned ``bullying powers'' for what he said was the misuse of science to develop weapons of mass destruction and referred to allegations of domestic spying by the U.S. on its own citizens.

``They even violate individual and social freedoms in their own nations under that pretext,'' Ahmadinejad said. ``They do not respect the privacy of their own people. They tap telephone calls and try to control their people.''

Christopher French, a 33-year-old screenwriter who attended the speech, described Bollinger's pointed attack on Ahmadinejad ``very bold'' and said he was pleased Columbia agreed to allow the Iranian president to speak.

``A leader of a tremendously powerful nation had to answer to a room of 600 people, most of whom were critical of his ideas,'' French said. ``The fact that he was willing, as a leader, to subject himself to that kind of criticism and challenge, that for me is what made today more valuable.''

To contact the reporter on this story: Ken Fireman in Washington at kfireman1@bloomberg.net; Janine Zacharia in New York at jzacharia@bloomberg.net

Last Updated: September 24, 2007 18:53 EDT