Ahmadinejad rose to applause, and after a religious invocation said Bollinger's opening was "an insult to information and the knowledge of the audience here".
He blamed the university president's "unfriendly treatment" on the influence of the US media and politicians ahead of his visit.'Evil has landed'
Ahead his appearance at Columbia, the front page of New York's Daily News
said: "The evil has landed," while The New York Post
called Ahmadinejad the "Madman Iran Prez".
"The countries that feel threatened ... should prepare for defence, and even counterattack"
Adolfo Talpalar, Stockholm, Sweden
Send us your views
Thousands of people gathered outside the United Nations headquarters on Monday to protest against Ahmadinejad's visit to New York.
"We're here today to send a message that there is never a reason to give a hatemonger an open stage," Christine Quinn, speaker of New York City's council, said.
Outside the university lecture hall where Ahmadinejad was to speak, several hundred protesters raised their objections to the event. Some linked arms and sang traditional Jewish folk songs about peace and brotherhood.
Inside, many students were wearing T-shirts with the message "Stop Ahmadinejad's Evil".Holocaust denial
Ahmadinejad rejected accusations that he has denied the Holocaust actually happened, but argued for more research to be conducted on the subject.
|"I said, granted this [the Holocaust]|
happened, what does it have to do with the Palestinian people"
Mahmoud Ahmadinejad, Iranian president
"I'm not saying that it didn't happen at all," he said. "I said, granted this happened, what does it have to do with the Palestinian people."
He used his 30-minute speech to repeat Tehran's insistence that its nuclear ambitions were focused on meeting the country's electricity needs.
Washington says Iran is seeking to produce nuclear weapons.
"We do not believe in nuclear weapons. Period. This goes against the whole grain of humanity," Ahmadinejad said.
During the question-and-answer session he denied that homosexuals were persecuted in Iran.
"In Iran we do don't have homosexuals like in your country," he said, sparking laughter from the audience.
"In Iran we do not have this phenomenon. I do not know who has told you we have it."