Iran has sealed the entrances of tunnels at the Isfahan nuclear complex, apparently to prevent a potential US or Israeli commando raid or mitigate damage from an airstrike, The Telegraph reported.

Axar.az reports that satellite imagery shows three tunnel entrances fully covered with soil. A Washington-based security institute said the move likely reflects serious Iranian concerns about a possible military strike on its hardened nuclear facilities. Similar defensive preparations were reportedly observed before US strikes on Iranian nuclear sites last year.

The development comes amid renewed US-Iran nuclear talks in Oman, described as a positive initial step by both sides. However, tensions remain high. Former President Donald Trump has warned of tough action if negotiations fail and threatened additional military deployments.

At the same time, Iran has displayed heightened military readiness. The Revolutionary Guards unveiled the Khorramshahr 4 ballistic missile, and officials signaled more “strategic surprises” to come. Military leaders warned they are in higher defensive readiness than during last year’s brief conflict with Israel.

Iran maintains its nuclear program is peaceful and insists talks focus solely on nuclear issues and sanctions relief. Meanwhile, Israeli Prime Minister Benjamin Netanyahu is in Washington to discuss Iran, calling the negotiations the top priority.