Iran is ramping up fortifications at its key nuclear facilities as tensions with the United States simmer. Fresh satellite imagery reveals tunnel entrances at the Isfahan site buried under soil and new structures built over parts of Isfahan and Natanz, signalling heightened defensive readiness. The developments come amid reports of unexploded U.S. bunker-buster bombs at Iranian sites following the 2025 conflict, even as indirect nuclear talks between Washington and Tehran continue through Omani mediation. With Iran insisting sanctions relief is key to any uranium dilution and the U.S. maintaining pressure, the region appears caught between diplomacy and deterrence.