Israel Believes Iran Moved Enriched Uranium to Fortified Underground Site Near Tehran

Israeli intelligence sources believe that after the 2025 war with Israel, Iran transferred advanced centrifuges and part of its enriched uranium stockpile to a heavily fortified underground facility south of Tehran known as Mount Machoosh. This assessment was shared with CNN by an Israeli source involved in the matter. The site, deeply buried and heavily guarded, has been monitored by Israeli intelligence for months as it is considered one of Iran's key nuclear facilities. Its central location in Iran and underground positioning make it a difficult target for both the US and Israel.

CNN previously reported that Iran has intensified efforts to secure its uranium stockpile, which is close to weapons-grade levels, by deliberately collapsing tunnels and blocking entrances with explosives. Iran reportedly holds about 440 kilograms of enriched uranium, and removing this material remains a primary objective for Israel and the United States in their conflict with Iran. Israel estimates that some of this uranium was moved to Mount Machoosh, a claim first reported by The Wall Street Journal.

The Israeli source noted that construction and activity at the site increased following the 12-day war between Israel and Iran in June 2025. During the conflict's final stages, the US struck three Iranian nuclear sites, Fordow, Natanz, and Isfahan, but did not target Mount Machoosh. In December, an Israeli official told CNN that there are continuous signs and messages indicating Iran is rearming, enhancing its capabilities, and preparing for further attacks.