A senior Israeli official told The New York Times on Thursday that some of Iran’s highly enriched uranium stockpiles likely survived the recent United States and Israeli strikes on Tehran’s nuclear facilities — and may still be accessible to Iranian nuclear scientists.

A senior Israeli official says Israel believes deeply buried stocks of enriched uranium at one Iranian nuclear facility hit by the U.S. military are potentially retrievable.

The assessment came as experts are trying to determine how long it would take Iran to rebuild its nuclear program in the aftermath of U.S. and Israeli strikes.