Inspectors from the UN nuclear watchdog found “nothing to be worried about” at Iran’s recently-revealed uranium enrichment site at Qom, International Atomic Energy Agency chief Mohamed ElBaradei said during an interview with the New York Times which was published Thursday.

ElBaradei said that the site was built as a back-up, in case the enrichment plant at Natanz was destroyed. “The idea was to use it as a bunker under the mountain to protect things,” he was quoted as saying. “It’s a hole in a mountain.”