Israel believes at least some of Iran’s highly enriched uranium was buried by U.S. strikes and not destroyed or moved beforehand.

Some of Iran’s enriched uranium at Fordo and Natanz survived the attacks by the United States in June and may still be accessible, according to an anonymous official who spoke to The New York Times. However, the official said that it would be hard for Iran to transport the enriched uranium out of the facilities.

Israel believes that Iran could potentially retrieve enriched uranium buried beneath one of the three facilities struck by US forces last month, according to a senior Israeli official.