Kolang mountain draws US threat amid suspected Iran nuclear work

An Iranian mountain that US President Donald Trump has threatened to attack is suspected of concealing a deeply buried nuclear complex, while Tehran denies that nuclear work is taking place there.

Trump said Tuesday that US forces would soon hit Mount Kolang, known in English as Pickaxe Mountain, "very heavily". Last week, he described the mountain as a possible target. Iranian foreign ministry spokesman Esmaeil Baqaei called Trump's comments a fabricated pretext for aggression.

The mountain is close to the Natanz nuclear enrichment complex in central Iran. The source item says Natanz was attacked last year when the United States and Israel launched a 12-day war against Iran.

Western experts say construction work on the suspected underground nuclear complex at Kolang began in 2020, probably after a fire at the Natanz centrifuge assembly hall that was believed to have been a sabotage attempt. Ali Akbar Salehi, then head of Iran's nuclear programme, said at the time that new halls would be built in the heart of the mountain near Natanz.

The United States used GBU-57 bunker bombs to attack the Natanz and Fordo nuclear sites in June last year. The bombs can penetrate several metres of concrete before exploding. Kolang was not attacked then and has not been targeted in the war that began on February 28, according to the Institute for Science and International Security, or ISIS.

Mohammad Hassan Najmi, an international relations expert, said Iranian authorities planned to make installations deeper under Kolang after several bombs were fired at Fordo last year.

In a July 14 note based on satellite images, ISIS said the new installation was at least 100 metres under the mountain, was not operational and remained under construction. James Acton, a nuclear issues expert with the Carnegie Foundation, said that depth would be beyond the penetration range of GBU-57 bombs. He said US bombs could destroy access tunnels, but that would not be a decisive change.

ISIS said the space beneath the mountain could be large enough to house a centrifuge enrichment plant capable of producing weapons-grade uranium.

The Wall Street Journal reported Tuesday that Israeli intelligence services had assured the United States that thousands of centrifuges were transferred under Mount Kolang last fall.

Several Iran experts described the timing of that reported information as striking because Trump's recent public focus has been on reopening the Strait of Hormuz, while the nuclear issue is critical for Israel.