President Obama slammed Iranian President Mahmoud Ahmadinejad Friday for suggesting before the U.N. General Assembly that the Sept. 11 terror attacks were an inside job, describing the comments as "hateful" and inexcusable." 

Obama personally responded to the Iranian leader's remarks in an interview with BBC Persian. He said the Iranian leader was once again demonstrating the difference between his regime and the "respectful and thoughtful" Iranian people. 

"It was offensive. It was hateful -- and particularly for him to make the statement here in Manhattan, just a little north of Ground Zero, where families lost their loved ones, people of all faiths, all ethnicities who see this as the seminal tragedy of this generation," Obama said. "For him to make a statement like that was inexcusable." 

Ahmadinejad defended his remarks Friday. In an exclusive interview with Fox News in which he was asked to explain himself, the Iranian president said he was not passing judgment and merely calling for a "fact-finding mission." 

"I did not give an opinion of my own. I actually suggested that a fact-finding group and mission be formed to delve into the truth," he told Fox News. "Do you think that the entire world has to accept what the U.S. government tells them, or do you think that perhaps a fact-finding mission is necessary?" 

Asked about Al Qaeda taking credit for the attacks, Ahmadinejad said an inquiry could "shed light" on the perpetrators. 

"Who was it backed by and supported? All these should come to light," he said. 

The president expressed disbelief Friday at Ahmadinejad's comments before the General Assembly. The Iranian leader is well-known for making outrageous remarks in public, but the U.N. speech was sharply condemned by U.S. officials and others. 

"For Ahmadinejad to come to somebody else's country and then to suggest somehow that the worst tragedy that's been experienced here, (an) attack that killed 3,000 people, was somehow the responsibility of the government of that country, is something that defies not just common sense but basic sense -- basic senses of decency that aren't unique to any particular country," Obama said. "They're common to the entire world."

The president made passing reference to Iran in his U.N. address Thursday morning, urging the country to come clean on its nuclear program. Ahmadinejad, taking the podium in the afternoon, used his address to assail the "Zionist regime" and spread conspiracy theories about the 2001 attacks -- prompting the U.S. delegation to walk out. 

Ahmadinejad claimed most people believe the U.S. government "orchestrated the attack to reverse the declining American economy and its grip on the Middle East in order to save the Zionist regime." 

The Iranian president said Friday that his nation was "saddened" by the loss of life in the  terror attacks but called for the inquiry to investigate the "true reason behind September 11."