Iran Moves Centrifuges Underground as U.S. Strikes Enter Their 10th Night

U.S. strikes continue as Iran strengthens underground nuclear sites

The U.S. has now logged a tenth consecutive night of strikes on Iran at the same time reports say Tehran has moved uranium-enrichment equipment underground. That combination shifts the negotiation away from a simple deal closure and toward a harder verification problem.

Satellite analysis earlier this month showed tunnel entrances being strengthened at Pickaxe Mountain near Natanz, with fresh concrete and construction activity indicating the complex is being made more resilient. BBC Verify and the Institute for Science and International Security said the facility may protect enrichment activities or key equipment, but also said its exact purpose and operational status remain unclear. Even so, the fortification before any new agreement adds a complicating factor for talks.

Monitors have found no evidence of uranium enrichment since the ceasefire, and assessments say Iran's centrifuge program remains destroyed. That does not mean the latest moves have no consequence. If Iran keeps enrichment hardware or equipment sheltered underground, any future agreement will still need broader access, clearer disclosure, and tougher monitoring.

Verification, not real-time detection, is now the main problem

The immediate question is not whether the underground site is running today. Monitors have found no evidence of any uranium enrichment since the ceasefire, and Natanz's centrifuges were described as severely damaged or destroyed. The harder question is whether inspectors can verify what remains below ground and reverse it before construction makes access more difficult.

Natanz was built to resist inspection as well as damage

Natanz was designed for depth and denial. Its underground enrichment facility is protected by roughly 7.6 metres of concrete, and the complex includes underground buildings designed to hold 50,000 centrifuges each. That helps explain why the physical infrastructure can remain strategically relevant even after hardware has been damaged.

What remains underground still matters

The central risk is that enriched material or centrifuge components survive in places that are hard for monitors to clear. Post-strike assessments say enriched uranium stocks appear to remain bottled up in underground facilities at several sites, and that the underground Natanz Fuel Enrichment Plant may hold intact centrifuges, components, or equipment. If that proves to be the case, the bottleneck will not be detection from outside. It will be access inside.

Strikes appear to have inflicted real damage on Iran's enrichment program. The remaining challenge for diplomats and inspectors is whether they can still verify what is underground, confirm what is broken, and remove or disable what matters before further construction makes that task harder.