The Iranian Foreign Minister says he has spoken by phone with the director of the U.N.’s nuclear watchdog agency after a report from the agency said Iran is further increasing its stockpile of uranium enriched to near weapons-grade levels.

A classified International Atomic Energy Agency report found Iran, since February, produced 300 pounds of uranium enriched to 60%, a step away from weapons-grade.

The U.N. atomic agency reports that Iran hasn’t cooperated with a nuclear probe, raising the prospect of a snapback of sanctions on Tehran.