Iranian state television quoted Ahmadinejad as saying Iran "will never give up its right to use peaceful nuclear energy."
Ahmadinejad, who was reportedly speaking to a crowd of thousands in Ilam Province, some 800 kilometers southwest of Tehran, said Iran will develop nuclear technology "to the limit."
Iran has been under intense pressure to curb its nuclear program. Western countries suspect Iran is trying to develop nuclear weapons.
The International Atomic Energy Agency (IAEA) has warned Iran that it could be referred to the U.N. Security Council, which has the power to impose sanctions on the country.