The above-ground pilot enrichment plant at Iran's Natanz nuclear site has been destroyed, U.N. nuclear watchdog chief Rafael Grossi told the Security Council on Friday.

"At present, the Iranian authorities are informing us of attacks on two other facilities, namely the Fordow fuel enrichment plant and at Isfahan," the International Atomic Energy Agency's Grossi told the 15-member council.

"At this moment we do not have enough information beyond indicating that military activity has been taken place around these facilities as well."