The International Atomic Energy Agency (IAEA) said Iran’s enriched uranium stockpile had reached 2,105kg.
Iran insists its nuclear programme is exclusively for peaceful purposes. It comes after Iran gave IAEA inspectors access to one of two suspected former nuclear sites.
The agency said it would take samples at the second site later this month.
Last year, Iran began deliberately and publicly reneging on commitments it had made under the international nuclear accord, signed in 2015 by Iran, China, France, Germany, Russia, the UK and the US.