His comments came as the European Union said that its nuclear talks with Iran had failed to find agreement and there was "no choice" but to return the matter to the UN Security Council for possible sanctions.
"Some oppressive countries intend to create discord in order to dissuade the Iranian nation from reaching the summits of dignity and glory, including using nuclear technology for peaceful purposes," said Ahmadinejad, according to the IRNA agency.
"But with God's kindness they will be defeated in this arena too," he said as he broke his Ramazan fast with an iftar meal late on Tuesday.
The United States is leading a drive for UN sanctions against Iran after it failed to obey a succession of deadlines to halt sensitive uranium enrichment, a process the West fears could be diverted to make nuclear weapons.
However Iran insists its right to the full nuclear fuel cycle is enshrined in international law and that its nuclear programme is solely aimed at generating energy.

Copyright AFP (Agence France-Presse), 2006