He added that "every week we install a new series."
Iranian state broadcasting quoted Ahmadinejad as making the claim in a speech to Islamist students.
The UN nuclear watchdog agency, the International Atomic Energy Agency (IAEA), estimated in a report made public in late August that Iran has just under 2,000 centrifuges operating at its facility in Natanz.
The UN Security Council has passed two rounds of sanctions demanding that Tehran cease uranium enrichment, with U.S. officials signaling their intention to seek further measures if enrichment and work on a heavy-water research reactor continue.
Iran's Foreign Ministry said today that if the Security Council passes a third round of sanctions, Tehran will consider unspecified new options.
The United States has accused Tehran of seeking nuclear weapons, and U.S. President George W. Bush has said Iran's possession of such a weapon is "unacceptable."
IAEA Director-General Muhammad el-Baradei has estimated that Iran could be as little as three years from developing an atomic bomb, if that is its desire.
El-Baradei told the German news magazine "Der Spiegel" in an interview published on September 1 that a recent agreement between the IAEA and Tehran to map out Iran's nuclear activities offers what could be that country's "last chance" to resolve the dispute. He said Iran has until November or December to prove its good intentions.
Iranian officials consistent reject accusations that they are trying to build nuclear weapons.