Iran suspected nuclear site work surged, CSIS says

A suspected underground Iranian nuclear site at Pickaxe Mountain has seen a surge in construction this year, according to a review of satellite imagery published Wednesday by the Center for Strategic and International Studies.

The Washington-based think tank said it reviewed imagery spanning six years, with the latest image from August 9. Its analysts wrote that the images showed more road activity at Pickaxe Mountain in 2026 than at any point in the site's history.

The analysts said the activity corresponded to the raising and hardening of portal accesses, paving of the internal road network, reinforcement around access areas and the flattening and removal of excavation spoil.

Pickaxe Mountain is near Natanz, where Western intelligence suspects Iran is building an undeclared enrichment facility. CSIS said it could neither refute nor substantiate a reported Israeli intelligence claim that Iran had moved centrifuges into Pickaxe Mountain.

US President Donald Trump threatened in July to strike Pickaxe Mountain during the war with Iran, but apparently did not follow through on the threat. The International Atomic Energy Agency has requested information about Pickaxe Mountain and access to the facility, and CSIS said Iran has reportedly never responded.

CSIS analysts wrote that the deeply buried granite fortification would be difficult to destroy even with the heaviest non-nuclear US munitions.

The US-Iran war is in its seventh month. On Wednesday, Iran launched fresh attacks against US targets in the Middle East in retaliation for American strikes on Iranian oil tankers, deepening the armed conflict.