An Iranian envoy is denying allegations that Tehran worked on developing nuclear arms at a military facility and then covered up the site to hide suspected clean-up efforts.

The comments by Ali Asghar Soltanieh are a rare instance of Iran acknowledging concerns about the Parchin site. The International Atomic Energy Agency suspects a building there was used to test explosives needed to set off a nuclear charge.

Iran denies any interest in nuclear weapons but has avoided public comment on Parchin fears while refusing agency experts access. Satellite images from last month appear to show that a tarp has been put over the suspect building, preventing satellite monitoring of an alleged clean-up.

Soltanieh, Iran's IAEA delegate, said Wednesday without elaboration that the activities have "nothing to do" with agency concerns.