Iran has fortified its underground stockpiles of highly enriched uranium by collapsing access tunnels and planting explosive mines around entrances, according to US intelligence sources cited by CNN. The measures, taken over recent weeks, are a direct response to President Donald Trump's public suggestion that American forces might seize the material. The roughly 500 kilograms of near-weapons-grade uranium, much of it believed to be at the Isfahan nuclear complex, is now buried under rubble and protected by booby traps, complicating any future verification or removal.

Viewed from Washington, the fortifications represent a significant obstacle to the emerging peace deal that Trump expects to sign on Sunday. US negotiators have demanded that Iran surrender all enriched uranium to dismantle its nuclear programme, but the new obstacles mean that even if an agreement is reached, accessing the stockpile would require heavy engineering, mine clearance, and nuclear specialists. Analysts in London note that the Iranian move mirrors a pattern of pre-emptive hardening seen in other negotiations, where Tehran seeks to strengthen its bargaining position by making concessions physically difficult to reverse.

From Tehran's perspective, the fortifications are a defensive measure against what it sees as credible threats of US military intervention. The US Chairman of the Joint Chiefs of Staff, General Dan Caine, reportedly drew up a secret plan for a ground operation to seize the uranium, but Trump was warned that such a move could escalate into a broader conflict and derail talks. The Iranian leadership, viewing the US as untrustworthy, has chosen to secure its most valuable nuclear assets against a possible raid, even at the cost of complicating a future diplomatic solution.

The standoff leaves both sides in a precarious position. While the peace deal remains on the table, the physical barriers to dismantling Iran's nuclear stockpile could become a sticking point in implementation. Experts caution that the longer the uranium remains buried and booby-trapped, the harder it will be to verify its status or ensure it does not fall into unauthorised hands. The coming days will test whether diplomatic momentum can overcome the new realities on the ground.