"Any sanctions against our country are illegal," he said in an interview with Japanese broadcaster NHK, carried by Iranian national media. "We have not so far demonstrated a tough response to sanctions."
"...the Iranian nation might respond, and Iran might impose sanctions against those states," Ahmadinejad said, without elaborating.
Iran, which holds the world's third-largest proven oil reserves, is already under three sets of UN sanctions over suspicions it seeks to build nuclear weapons under the guise of a civilian program. It is facing more stringent punitive measures for its refusal to halt uranium enrichment.
Tehran has repeatedly denied allegations it is seeking a nuclear bomb and insists on its right to civilian nuclear research.
Ahmadinejad also said the next U.S. president, whoever he might be, must change policies, and focus on domestic problems.
The next president "must drop his predecessors' policies, which do not meet the interests of the Americans themselves and the world community," he said, adding that the new U.S. leader would also have to review his approach to Iran.
Washington has not ruled out the use of military action to force the Islamic Republic to drop its nuclear ambitions.
