"The process is underway at the nuclear facility in central Iran. We are now getting nine grams per hour," said Ali Akbar Salehi on state television.
Salehi noted that experts have produced uranium to the purity of 60 percent at the Natanz facility.
Earlier Friday, parliamentary speaker Mohammed Bagher Ghalibaf announced on his Twitter account that Iranian scientists had successfully started enriching 60 percent uranium at 12.40am.