The nuclear mountain that haunts Israel

Buried half a kilometre underground, Iran's Fordow enrichment facility is the ultimate test of Israeli air power.

- John Paul Rathbone and Charles Clover

To Israeli military planners, it is akin to Mount Doom: a tightly guarded nuclear enrichment plant, buried half a kilometre beneath a mountain, which is ringed by air defences and symbolically situated near the ancient religious city of Qom.

To Tehran, the Fordow facility symbolises its desire to safeguard its nuclear programme, designed to survive a full-frontal attack, with enough centrifuges and highly enriched uranium intact to potentially produce a nuclear weapon, or "break out".

Buried under hard rock, and encased in reinforced concrete that puts it beyond the destructive reach of any of Israel's publicly known weapons, it is also a symbol of Iran's strategic anxiety.

"Fordow is the be-all and end-all of Iran's nuclear operation," said Mr Behnam Ben Taleblu, a senior fellow at the Foundation for Defence of Democracies (FDD), a US think-tank.

Iran on June 14 confirmed that Fordow had been attacked, the semi-official Isna news agency reported, citing a spokesperson for the country's atomic energy organisation, although the damage was limited.

By contrast, Israel succeeded in destroying Iran's larger above-ground pilot enrichment plant at Natanz, UN nuclear watchdog chief Rafael Grossi told the Security Council on June 13.

Its underground centrifuge halls may have been rendered useless by extensive damage to Natanz's electricity supplies, according to analysis of open-source satellite images by the Institute for Science and International Security think-tank.

"Fordow will be challenging without the US. It is heavily fortified and deep under a mountain. I'm not sure how much damage we can do there," said Mr Danny Citrinowicz, an Iran expert at the Institute for National Security Studies in Tel Aviv.