In an interview with state broadcaster IRIB, Ahmadinejad did not directly mention a U.N.-brokered nuclear fuel deal meant to allay suspicions about Iran's disputed nuclear ambitions.
The plan for Iran to part with stocks of potentially explosive nuclear material in exchange for fuel to keep a nuclear medicine facility running has faltered over Iranian calls for amendments and more talks, rejected by Washington.
"One of the most important issues of today is definitely nuclear cooperation at the international level, whether in building a power station or reactor or whether it is about Iran's presence in the global fuel bank," Ahmadinejad said.
He did not elaborate.
In June, a uranium fuel supply plan hailed by U.S. President Barack Obama as a way to stem the spread of nuclear arms stalled in talks at the International Atomic Energy Agency (IAEA) because of resistance from developing nations.
The U.N. nuclear agency and industrialized countries argued that a multilateral uranium-enrichment center would best meet growing global nuclear energy demand while dissuading countries from building proliferation-prone enrichment plants themselves.
Emerging countries fear that "multinationalizing" control over the fuel cycle would curb their right to home-grown atomic energy to generate electricity.
Iran already has one enrichment plant operating and has rejected demands for it to halt activity that can have both civilian and military purposes, in return for economic and political incentives.
Ahmadinejad said the issue of stopping Iran's nuclear activities was "finished," IRIB reported on its website.
"Those people who yesterday told us that we should suspend our activities … (today) they cannot say anything," he said, adding Iran would protect its "big nuclear achievements" with determination.
Iran says its nuclear program is aimed at generating electricity, rejecting Western accusations it is seeking to develop bombs, based on its past failures to declare sensitive activity to the IAEA and continued limitations on IAEA access.
In talks with six powers in Geneva on October 1, Iran agreed in principle to send the bulk of its low-enriched uranium to Russia and France for further processing and conversion into fuel plates for the Tehran reactor, Western officials said.
They said Iran later balked at fleshing out details and seemed to retreat from the point of the Geneva deal — to minimize the risk of Iran "weaponizing" enriched uranium.
(Reporting by Ramin Mostafavi and Hossein Jaseb; writing by Fredrik Dahl; editing by Andrew Dobbie)
