The IAEA closely monitors Iran's nuclear facilities and states in a new report that the country now has 164.7 kilograms of uranium enriched to 60 percent.
This is 22.6 kilograms more than in May when the IAEA published its previous report.
Uranium used in nuclear weapons is usually enriched up to 90 percent.
The IAEA's report comes just days after Iran's supreme leader, Ayatollah Ali Khamenei, opened the door for negotiations with the US on the country's nuclear energy program.
In a speech, he told the country's government that there was "no harm" in cooperating with the "enemy" - but in the same breath warned against trusting the enemy, namely Washington.
