"Our enemies believe that they can make us retreat," Ahmadinejad said, "but who are they to be suspicious of our peaceful nuclear program. It is we who are suspicious of their arsenal of weapons of mass destruction."
He made the remarks in a speech marking the 25th anniversary of the creation of Iran's voluntary Basij militia.
The International Atomic Energy Agency (IAEA) on 25 November called on Iran to accept a Russian proposal for Iran to enrich uranium in Russia.
The United States has accused Iran of seeking nuclear-weapons technology under the cover of a peaceful nuclear energy program. Tehran denies the charge.