US-Iran Deal Day 4 Unsigned: Trump Returns Amended MOU Drafts Seeking Stricter Nuclear Terms; IAEA Reports Record Iran HEU Stockpile

June 1, 2026 — The US-Iran nuclear and Hormuz agreement confirmed tentatively by CNN on May 28 remains unsigned entering its fourth day. On June 1, President Trump sent back amended drafts of the memorandum of understanding, seeking stricter nuclear commitments from Tehran and expanded provisions governing Strait of Hormuz reopening guarantees and verification protocols. The amended drafts effectively extend the timeline for any formal signing by at least another week, according to reporting tracking the negotiation. Compounding the diplomatic pressure, the International Atomic Energy Agency (IAEA) reported on May 31 that Iran had amassed a record amount of military-grade enriched uranium — adding urgency to the US demand for enhanced HEU disposal provisions in the Phase 2 nuclear talks framework. The core MOU framework under negotiation: Phase 1 = Iran clears mines from the Strait, Hormuz reopens with no tolls, US lifts the naval blockade, sanctions waivers enable Iranian oil sales to resume; Phase 2 = 60-day nuclear negotiations on enrichment suspension limits and HEU stockpile removal under IAEA verification. The Strait of Hormuz enters Day 4 of the post-tentative-agreement period still physically closed — approximately 750 vessels remain trapped, approximately $6 billion per month in Iranian oil exports blocked, and US gasoline prices holding at approximately $4.48/gallon (Week 14 of closure). General Asim Munir of Pakistan continues as the principal back-channel intermediary connecting the US negotiating team (Vance, Witkoff, Kushner) with Iran's side. The congressional opposition bloc — 52 senators and 177 House members who wrote to Trump on May 14 opposing any deal permitting Iranian enrichment — continues to constrain the domestic political space for a formal announcement. Both sides are assessed as negotiating in earnest but the gap between 'tentative agreement' and a signed deal is proving more stubborn than VP Vance suggested on May 28 when he acknowledged only 'a couple of language points' remained.