"They [the West] should know that our nation will preserve all its rights with logic and unity," Ahmadinejad said in a televised address in the western city of Hamedan.
Ahmadinejad comments mark a shift from his previous position that Iran would only discuss the issue with the International Atomic Energy Agency (IAEA), the United Nations nuclear watchdog.
Tehran also agreed to co-operate with an IAEA investigation into allegations that it tried to make nuclear arms.
Melissa Fleming, an IAEA spokeswoman, says the agency hopes Iran will provide the necessary clarifications about the allegations in May.
She said on Wednesday that an agreement on the issue had been reached during talks in Tehran earlier this week between Iranian officials and Olli Heinonen, the IAEA deputy director general.
Iran insists its nuclear programme is aimed only at producing electricity so that the world's fourth-largest crude exporter can sell more of its oil and gas abroad.
Tehran has failed to convince the West, which accuses the Islamic state of secretly trying to produce nuclear weapons.
The UN Security Council has imposed three rounds of sanctions on Tehran for not halting its nuclear activities.