The UN nuclear watchdog has indications from satellite images of possible "activities" taking place at an Iranian military site that add urgency to its request to visit the Parchin facility, Western diplomats said on Wednesday.
They said Herman Nackaerts, head of nuclear inspections at the International Atomic Energy Agency (IAEA), made the comment about Parchin at a closed-door briefing for member states of the Vienna-based UN agency.
He did not specify what kind of activities may be taking place at Parchin and whether they may involve efforts by Iran to clean it up.
The IAEA wants to visit Parchin as part its probe into possible military links to Iran's nuclear programme. Iran says its nuclear work is entirely peaceful.