The head of the United Nations nuclear watchdog has said that it would take Iran just weeks to have enough enriched uranium to make a nuclear bomb, and that Tehran’s activity, alongside the limited access it grants to its facilities, “raises eyebrows.”

But International Atomic Energy Agency chief Rafael Mariano Grossi told Deutsche Welle in a report published Monday that attacking Iran’s nuclear facilities should be a “no-go.”

Grossi said that Iran is “weeks rather than months” away from having enough enriched uranium to make a nuclear weapon.