UNITED NATIONS — President Mahmoud Ahmadinejad of Iran stoked the anger of Israel, the United States, Syrian insurgents and gay-rights advocates Monday, using the first full day of his final visit to the United Nations as Iran’s leader to assert that he has no fear of an Israeli attack on its nuclear facilities, regards the Israelis as fleeting aberrations in Middle East history, is neutral in the Syria conflict and considers homosexuality an ugly crime.

In a series of public appearances that included a breakfast meeting with selected members of the media, a speech on the rule of law at a U.N. conference and a CNN interview broadcast Monday evening, Ahmadinejad sought to portray Iran as a principled and upstanding member of the global community.

But the Iranian leader, known for his denials of the Holocaust and other inflammatory language, ignored a warning by the secretary-general of the United Nations, Ban Ki-moon, against making provocative statements. Instead, he offended a wide range of targets and prompted the Israeli delegation to walk out of the U.N. conference in protest.

In what may have been his most incendiary remarks Monday, Ahmadinejad belittled what he characterized as the insignificant history of Israel, compared with the long history of Iran. He told reporters and editors at the breakfast meeting that the Israelis had been around the region for only 60 or 70 years, in contrast to the Iranians, whose civilization has existed for thousands of years.

“They have no roots there in history,” Ahmadinejad said of the Israelis. “They do not even enter the equation for Iran.”

Israel’s ambassador, Ron Prosor, left the conference, saying in a statement that “Ahmadinejad showed again that he not only threatens the future of the Jewish people, he seeks to erase our past. Three thousand years of Jewish history illustrate the clear danger of ignoring fanatics like Iran’s president, especially as he inches closer to acquiring nuclear weapons.”