Columbia University President Lee Bollinger (April, 2007 file photo)

The host of a controversial U.S. speech by Iran's president has told Mahmoud Ahmadinejad that he exhibits all the signs of a "petty and cruel dictator."

Mr. Ahmadinejad's appearance at Columbia University Monday was among the most contentious of his visit to New York this week, which has sparked protests from rights groups, the media and politicians. Thousands of demonstrators gathered outside the university during his appearance.

University President Lee Bollinger challenged Mr. Ahmadinejad to answer questions on Iran's nuclear program, as well as oppression of intellectuals, homosexuals and others in Iran. The Iranian leader said his country did not have homosexuals, a comment that provoked laughter from the audience.

Mahmoud Ahmadinejad responds to a question during an interview in New York, 24 sep 2007

Mr. Ahmadinejad said that Bollinger had insulted him and the audience. The Iranian president devoted his prepared comments to religious and philosophical ideas about the pursuit of truth.

The Iranian leader told Bollinger that he would answer questions, but on several occasions posed his own questions instead. He also would not directly answer on whether he seeks the destruction of Israel. He said his solution was a referendum of the people in the disputed areas.

Mr. Ahmadinejad addresses the United Nations General Assembly Tuesday.

Critics say Columbia University should not have given the Iranian leader a platform to speak. Bollinger said it was part of the American tradition of freedom of speech. He also said that Mr. Ahmadinejad's denial of the Holocaust made him seem ridiculous, and that he appeared either brazenly provocative or astonishingly uneducated.

During a speech earlier Monday to journalists, Mr. Ahmadinejad said the way the U.S. government is trying to manage the world is wrong and leads to bloodshed.

Mr. Ahmadinejad deflected questions about reports of the oppression of women and executions of reporters in Iran, accusing the media of distorting information. He told the American journalists it was their job, among other things, to disseminate moral behavior and purity.

U.S. Secretary of State Condoleezza Rice said Monday that it would have been wrong for the Iranian president to visit the World Trade Center site, as he requested, to lay a wreath for the victims of the September 11 terror attacks in 2001. New York police denied the Iranian leader's request on security grounds. U.S. President George Bush said last week he understood why the police would not want someone who is running a country that is, in his words, a state sponsor of terror, at the site.

The Bush administration alleges that Iran supports Shi'ite insurgents in Iraq, and that Tehran is seeking to obtain a nuclear weapon, charges Iran denies.

Mr. Ahmadinejad said he wanted to go to the World Trade Center site to express his sympathy for the victims. He added that it is also important to understand the root cause of the events.