The report comes at a sensitive time as Tehran and Washington have been holding several rounds of talks over a possible nuclear deal that U.S. President Donald Trump is trying to reach.
The report by the Vienna-based International Atomic Energy Agency — which was seen by The Associated Press — says that as of May 17, Iran has amassed 408.6 kilograms (900.8 pounds) of uranium enriched up to 60%. That’s an increase of 133.8 kilograms (294.9 pounds) since the IAEA’s last report in February.
That material is a short, technical step away from weapons-grade levels of 90%. A report in February put the stockpile at 274.8 kilograms (605.8 pounds).
The IAEA chief Rafael Mariano Grossi has stressed repeatedly that “Iran is the only non-nuclear weapon state enriching to this level.”
On Saturday, Grossi said he “reiterates his urgent call upon Iran to cooperate fully and effectively” with the IAEA.