US President Donald Trump has put Pickaxe Mountain – a suspected Iranian nuclear site buried deep underground – in the spotlight, saying it could become a target as Washington considers its next steps in the conflict.
Mr Trump told the Salem news channel that the US was monitoring the site and suggested a strike could come soon.
"Pickaxe is a possible, you know, target for a nice big, fat shot right in the front door," he said. "We'll probably give Pickaxe a shot relatively soon."
The comment came as American forces carried out strikes on Iran for a third straight night, amid rising tensions over the Strait of Hormuz. The US and Israel attacked Iran's nuclear sites in June last year and did so again in the war that began on February 28. A ceasefire put in place on April 8 has been repeatedly tested, with heavy exchanges of fire occurring again in the past week.
A wide range of nuclear-linked sites are reported to have been hit, including enrichment facilities at Natanz, the Khondab heavy water complex near Arak, uranium-conversion and metallurgy facilities at Isfahan and a yellow cake production plant in Ardakan, Yazd province.
So what is Pickaxe Mountain?
Known in Farsi as Kuh-e Kolang, the site is an underground complex built into a mountain near the Natanz uranium enrichment facility in central Iran. Pickaxe Mountain has been identified as one of Iran's newest underground nuclear-related sites.
Unlike older Iranian facilities, which are more exposed, Pickaxe Mountain appears to be designed around concealment and protection. Satellite imagery analysis by groups including the Institute for Science and International Security has indicated construction began in about 2020. Iran has described the facility as a centrifuge assembly plant, although UN inspectors have not been granted access to fully inspect the site.
Satellite imagery has shown extensive excavation and tunnel construction, but the exact purpose of the facility has not been publicly confirmed. Iran maintains that its nuclear programme is peaceful, while western governments and experts have raised concerns over the site's location, scale and design. The facility is reportedly buried up to 600 metres under granite.
A deeply buried facility could provide Iran with a secure location for sensitive nuclear activities and make it harder for any military strike to disable the site. Some weapons experts have questioned whether even the US military's most powerful bunker-buster bombs would be sufficient to destroy a facility built at such depths, although the extent of the site's vulnerability remains unknown.
