In an NBC-TV interview, the Iranian leader also did not offer a direct response when asked whether there were any conditions under which Iran would develop a nuclear weapon.
"We don't need nuclear weapons," Ahmadinejad said, speaking through an interpreter.
"We do not see any need for such weapons. And the conditions around the world are moving to favor our ideas," Ahmadinejad added.
Iran has repeatedly said it is enriching uranium only to generate electricity, not for fissile bomb material, although it has no nuclear power plants to use low-level enriched uranium.
Ahmadinejad said Iran would "never" halt work on its nuclear program to mollify Western skeptics.
Iran is set to attend talks on Oct. 1 with major powers worried about its nuclear strategy. U.S. Secretary of State Hillary Clinton said this week any talks with Iran would have to address the nuclear issue.
"We have always believed in talking, in negotiating, that's our logic. "Nothing has changed," Ahmadinejad said, speaking through an interpreter.
"If you are talking about the enrichment of uranium for peaceful purposes, this will never be closed down here in Iran," he said.
The P-5 plus 1 (the United States, Britain, China, France, Russia and Germany) is concerned that Iran's nuclear enrichment program is aimed at producing a nuclear weapon.
The International Atomic Energy Agency said on Thursday that it has no proof that Iran has or once had a covert atomic bomb program, dismissing a media report that the IAEA had concluded Iran was on its way to producing nuclear weapons.
In the NBC interview, Ahmadinejad also defended the legality of his re-election last spring, "I don't see any problems." (Writing by JoAnne Allen; Editing by Philip Barbara)
