Iran's nuclear program has once again emerged as a major obstacle in negotiations to end the US-Israel war on Iran, with Washington and Tehran remaining divided over uranium enrichment and the future of Iran’s nuclear stockpile. Iranian security chief Mohsen Rezaei insists that "even a particle of enriched uranium will not exit Iran at all," rejecting demands for Tehran to transfer its nuclear material abroad. Meanwhile, US Vice President JD Vance calls for meaningful reductions in enrichment capacity, as the US seeks a long-term, verifiable commitment from Iran not to rebuild its nuclear weapons capabilities. A June memorandum of understanding proposed reducing uranium enrichment levels under international supervision but left key details unresolved.