Iran Update Special Report, May 31, 2026
May 31, 2026
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The Institute for the Study of War (ISW) and The Critical Threats Project (CTP) at the American Enterprise Institute are publishing daily updates to provide analysis on the war with Iran. The updates focus on US and Israeli strikes on Iran and Iran and the Axis of Resistance’s response to the strikes. The updates cover events from the past 24-hour period.
Key Takeaways
US President Donald Trump has requested several amendments to the draft US-Iran memorandum of understanding (MoU) as the United States and Iran remain at odds over key issues. Officials said that Trump specifically requested amendments to the draft’s text about how and when the United States would secure Iran’s highly enriched uranium (HEU). A second informed source told Axios that Trump also requested changes to the draft MoU’s text on the Strait of Hormuz. Three US officials separately told the New York Times on May 30 that Trump is concerned about parts of the draft MoU that would involve the United States unfreezing Iranian funds. Islamic Revolutionary Guards Corps (IRGC)-affiliated media argued that it would be better to not reach an agreement than for Iran to accept a “bad deal” that failed to secure Iranian interests.
Anti-regime media, citing an unspecified informed source, claimed on May 31 that President Masoud Pezeshkian has submitted a resignation letter to Supreme Leader Mojtaba Khamenei. ISW-CTP cannot independently verify this report. Iranian state media denied this report and no Iranian officials have confirmed this claim at the time of this writing.
Toplines
US President Donald Trump has requested several amendments to the draft US-Iran memorandum of understanding (MoU) as the United States and Iran remain at odds over key issues. A senior Trump administration official and a second unspecified source told Axios on May 30 that Trump requested several amendments to the draft MoU.[1] The officials said that Trump specifically requested amendments to the draft’s text about how and when the United States would secure Iran’s highly enriched uranium (HEU).[2] The current draft MoU states that Iran would commit to not pursue a nuclear weapon but does not contain any Iranian commitments to hand over Iran’s HEU or halt enrichment.[3] The current draft states that the United States and Iran would discuss nuclear issues during a 60-day period after the parties sign the MoU.[4] Iranian officials have repeatedly insisted that Iran will not suspend uranium enrichment or transfer its HEU from Iran.[5]
A second informed source told Axios that Trump also requested changes to the draft MoU’s text on the Strait of Hormuz.[6] The source did not specify what specific changes Trump requested, however.[7] Trump previously called on Iran on May 29 to “immediately open” the Strait of Hormuz without tolls and to remove mines from the strait.[8] The United States and Iran have different definitions of “opening” the strait, however.[9] Iranian officials and media continue to claim that the strait is “open” despite the Islamic Revolutionary Guards Corps (IRGC) Navy forcing vessels to transit through Iran’s illegal traffic separation scheme.[10] Two unspecified US officials told Axios on May 28 that, under the current draft MoU, Iran would allow “unrestricted” shipping through the Strait of Hormuz, stop imposing tolls and harassing vessels in the strait, and remove naval mines within 30 days, while the United States would lift its naval blockade on Iranian ports.[11] Iranian officials have also claimed that Iran is charging vessels “protection fees” and “environmental fees” instead of “tolls.”[12] Iran remains the only power that has threatened civilian shipping in the Strait of Hormuz during this war, meaning that its “protection fee” is a protection racket that ships must pay to avoid Iranian attack.
Three US officials separately told the New York Times on May 30 that Trump is concerned about parts of the draft MoU that would involve the United States unfreezing Iranian funds.[13] Trump previously appeared to reject unfreezing Iranian funds on May 29, stating that “no money will be exchanged until further notice.”[14] Iranian officials have repeatedly stated that the United States must unfreeze frozen Iranian assets in order for Iran to accept any potential agreement.[15] An Iranian official affiliated with Iran’s negotiating delegation stated on May 30 that Iran could withdraw from a US-Iran agreement if the United States “does not meet its commitments,” including unfreezing Iranian funds.[16]
Unspecified informed sources told Israeli media that Iranian Supreme Leader Mojtaba Khamenei has not responded to either the current draft MoU or Trump’s proposed amendments.[17] IRGC-affiliated media argued that it would be better to not reach an agreement than for Iran to accept a “bad deal” that fails to secure Iranian interests.[18]
Anti-regime media, citing an unspecified informed source, claimed on May 31 that President Masoud Pezeshkian has submitted a resignation letter to Supreme Leader Mojtaba Khamenei.[19] Pezeshkian reportedly warned in an “unprecedented and critical tone” that the IRGC is wielding an outsized role in the regime.[20] ISW-CTP cannot independently verify this report. Iranian state media denied this report and no Iranian officials have confirmed this claim at the time of this writing.[21]
https://understandingwar.org/research/middle-east/iran-update-special-report-may-31-2026/