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Iran Update Special Report, May 18, 2026
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
Iran’s latest counterproposal does not appear to meet US demands. A senior US official and source briefed on the matter told Axios on May 18 that Iran’s counterproposal does not contain a commitment “about suspending uranium enrichment or handing over its existing stockpile of highly enriched uranium (HEU).” US demands have been and continue to be that Iran must give its HEU to the United States.
US President Donald Trump announced on Truth Social on May 18 that he canceled a scheduled US military strike against Iran that was planned for May 19. Trump’s announcement comes after Qatari, Emirati, and Saudi leaders asked Trump to suspend the strike “for two or three days” due to ongoing negotiations and concerns over Iranian retaliation. Trump, however, noted that he instructed the US military to remain prepared to launch a “full, large-scale assault” against Iran on short notice if negotiations fail.
Iran continues to formalize and institutionalize its claimed control over transit through the Strait of Hormuz in contravention of the UN Charter on the Law of the Sea (UNCLOS). Iran has incorrectly asserted that this is ”legal” under the UNCLOS because the Strait of Hormuz is within Iran’s territorial waters.
IRGC-affiliated outlets continue to threaten commercial and digital activity linked to the Strait of Hormuz as part of broader regime efforts to institutionalize Iranian authority over the waterway.
Toplines
Iran’s latest counterproposal does not appear to meet US demands. Reuters reported on May 18 that Iran sent a new proposal with similar terms to proposals previously rejected by the United States.[1] A senior US official and source briefed on the matter told Axios on May 18 that Iran’s counterproposal does not contain a commitment “about suspending uranium enrichment or handing over its existing stockpile of highly enriched uranium (HEU).”[2] The US official added that the Trump Administration believes Iran’s proposal is ”insufficient.” Islamic Revolutionary Guards Corps (IRGC)-affiliated media reported on May 18 that ”major disagreements” remain between the United States and Iran and stated that Iran would never agree to ”an end to the war in return for nuclear commitments.”[3] US demands have been and continue to be that Iran must give its HEU to the United States, dismantle its nuclear facilities, and pause uranium enrichment for at least 20 years.[4]
US President Donald Trump announced on Truth Social on May 18 that he canceled a scheduled US military strike against Iran that was planned for May 19.[5] Trump stated that Qatari Emir Sheikh Tamim bin Hamad al Thani, Saudi Crown Prince Mohammed bin Salman, and Emirati President Mohamed bin Zayed asked him to suspend the strike “for two or three days” due to ongoing negotiations.[6] A US official and an unspecified source told Axios that the three Gulf leaders warned that they would ”pay the price“ if the United States conducted new strikes on Iran and expressed concerns that Iran would retaliate by targeting their energy and oil infrastructure.[7] Trump noted that the Gulf leaders believe that the United States and Iran can reach a deal that is “very acceptable to the United States” and that would prevent Iran from obtaining nuclear weapons.[8] Trump added that he instructed US Defense Secretary Pete Hegseth, US Chairman of the Joint Chiefs of Staff General Dan Caine, and the US military to remain prepared to launch a “full, large-scale assault” against Iran on short notice if negotiations fail.[9]
Iran continues to formalize and institutionalize its claimed control over transit through the Strait of Hormuz in contravention of the UN Charter on the Law of the Sea (UNCLOS). The newly established Persian Gulf Strait Authority (PGSA) stated on X on May 18 that it serves as the “legal institution and representative authority” of the Iranian regime for managing transit through the strait.[10] Iran has incorrectly asserted that this is ”legal” under the UNCLOS because the Strait of Hormuz is within Iran’s territorial waters.[11] Article 37 of the UNCLOS states that straits ”used for international navigation between one part of the high seas or an exclusive economic zone and another part of the high seas or an exclusive economic zone” are international straits.[12] Article 38 guarantees that ”all ships and aircraft enjoy the right of transit passage” through such straits, and Article 44 prohibits bordering states–like Iran–from ”hampering” or suspending passage.[13] The PGSA added that navigation through the designated zone requires “full coordination” with the authority and warned that transit without authorization would be considered illegal.[14] This is an Iranian effort to hamper passage. Iranian state media separately highlighted that 1,500 vessels are currently waiting for Iranian permission to transit the strait as part of broader regime efforts to portray Iran as the sole authority responsible for managing transit through the strait.[15]
IRGC-affiliated outlets continue to threaten commercial and digital activity linked to the Strait of Hormuz as part of broader regime efforts to institutionalize Iranian authority over the waterway. IRGC-affiliated Fars News Agency reported on May 18 that Iran could impose permits, oversight measures, and sovereign fees on fiber-optic cables transiting the strait after implementing “management” over the strait.[16] Fars warned that disruptions to the corridor could impose high direct and indirect costs on the regional and global economy.[17] Major subsea cables, including the Asia-Africa-Europe 1 (AAE-1), FALCON, and the Gulf Bridge International Cable System, run through the Strait of Hormuz and support digital connectivity between Asia, the Gulf, and Europe.[18] Three of seven cables–FALCON, GBICS, OMRAN/EPEG cables–connect to Iran and run through the strait.[19] IRGC-affiliated Javan News previously warned that simultaneous damage to several major subsea cables, including through “deliberate actions,” could cause widespread disruptions to communications and digital infrastructure.[20] Fars also claimed that Iran could justify such measures under the 1982 UNCLOS and claimed Iran’s “absolute sovereignty” over the seabed and subsoil of its territorial waters.[21]
Maritime Development
US Central Command (CENTCOM) said on May 18 that US forces have redirected 85 commercial vessels and disabled four since the blockade on Iranian ports began on April 13.[22] US forces redirected 4 commercial vessels between 10:00 AM ET on May 17 and 1:00 PM ET on May 18.[23]
US and Israeli Air Campaign
Nothing significant to report.
Iranian Internal Dynamics
Nothing significant to report.
Israeli Campaign Against Hezbollah and Hezbollah Response
The Israel Defense Forces (IDF) conducted an airstrike killing a senior Palestinian Islamic Jihad (PIJ) commander near Baalbek, in northeastern Lebanon’s Bekaa Valley, on May 17.[24] The IDF announced on May 18 that the airstrike targeted PIJ Bekaa Valley operations commander Wael Mahmoud Abdel Halim.[25] Halim coordinated PIJ efforts to embed fighters into Hezbollah combat units and planned joint PIJ-Hezbollah attacks targeting Israeli forces in southern Lebanon, according to the IDF.[26] Israeli airstrikes in Lebanon have killed a small number of PIJ fighters and commanders, including PIJ’s military wing Al Quds Brigades commander Adham al Othman, in Lebanon since the current conflict began.[27]
Other Axis of Resistance Response
Likely Iranian-backed Iraqi militias launched three drones targeting Saudi Arabia on May 17.[28] The Saudi Defense Ministry stated on May 17 that it intercepted three drones launched from Iraq that entered Saudi airspace.[29] Iraqi media reported on May 18 that the Iraqi Ministry of Foreign Affairs expressed ”concern” about the incident.[30] This attack comes after likely Iranian or Iranian-backed Iraqi militias launched three drones targeting the Barakah Nuclear Power Plant in the United Arab Emirates (UAE) on May 17, one of which hit an electrical generator.[31] Likely Iranian-backed Iraqi militias have conducted several drone attacks targeting Gulf states since the onset of the US-Iran ceasefire in early April.[32]
Iranian-backed Iraqi militia Kataib Hezbollah Spokesperson Abu Mujahid al Aasaf warned on May 18 that the militia will retaliate in the event of renewed US and Israeli strikes on Iranian-backed Iraqi militias in Iraq.[33] He claimed that most US and Israeli “reconnaissance operations” originate from Jordan and warned the Jordanian government to learn from the events of the recent conflict, which is likely an attempt to deter the Jordanian government from allowing US forces to conduct strikes from Jordan.[34] Iranian-backed Iraqi militias repeatedly conducted drone attacks targeting US bases in Jordan before the ceasefire.[35]
Endnotes
[1] https://www.reuters.com/world/asia-pacific/pakistan-hands-us-revised-iranian-proposal-ending-war-2026-05-18/ [2] https://www.axios.com/2026/05/18/iran-peace-deal-offer-nuclear-unacceptable [3] https://t.me/Tasnimnews/416257 [4] https://www.bbc.com/news/articles/cgkpnnen5dzo [5] https://truthsocial.com/@realDonaldTrump/posts/116597121700043134 [6] https://x.com/BarakRavid/status/2056490684480122946 [7] https://www.axios.com/2026/05/18/trump-iran-attack-suspend-nuclear-talks [8] https://truthsocial.com/@realDonaldTrump/posts/116597121700043134 [9] https://truthsocial.com/@realDonaldTrump/posts/116597121700043134 [10] https://x.com/PGSA_IRAN/status/2056359507203142013 [11] https://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf [12] https://www.justsecurity.org/133996/legal-operational-strait-hormuz-transit-passage/; https://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf
[13] https://www.justsecurity.org/133996/legal-operational-strait-hormuz-transit-passage/; https://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf [14] https://x.com/PGSA_IRAN/status/2056359509296099548 [15] https://t.me/iribnews/339759 ; https://t.me/Nournews_ir/357023 [16] https://t.me/farsna/436350 [17] https://t.me/farsna/436350 [18] https://www.reuters.com/business/media-telecom/hormuz-digital-chokepoint-how-does-iran-war-threaten-subsea-cables-2026-04-28/ [19] https://www.submarinecablemap.com/ [20] https://www.javanonline dot ir/fa/news/1355990 [21] https://t.me/farsna/436350 [22] https://x.com/CENTCOM/status/2056377204590694844?s=20 ; https://x.com/CENTCOM/status/2056419563663921317 [23] https://x.com/CENTCOM/status/2056419563663921317 ; https://x.com/CENTCOM/status/2056014991078158472 [24] https://x.com/idfonline/status/2056345286146957487?s=20 ; https://t.me/MTVLebanoNews/70067 ; https://t.me/MTVLebanoNews/70069 [25] https://x.com/idfonline/status/2056345286146957487?s=20 [26] https://x.com/idfonline/status/2056345286146957487?s=20 ; https://x.com/JoeTruzman/status/2056356323831484866?s=20 [27] https://x.com/JoeTruzman/status/2056356323831484866?s=20 ; https://www.aa.com dot tr/en/middle-east/palestinian-group-says-its-commander-in-lebanon-killed-in-israeli-strike-in-beirut/3847153 [28] https://x.com/modgovksa/status/2056102093358854204 [29] https://x.com/modgovksa/status/2056102093358854204 [30] https://shafaq dot com/ar/سیاسة/العراق-يطلب-من-السعودية-تبادل-المعلومات-بش-ن-المسي-رات-لم-نرصد-ي-م-شرات [31] https://understandingwar.org/research/middle-east/iran-update-special-report-may-17-2026/ ; https://x.com/modgovae/status/2056014348993360147?s=20 ; https://x.com/ADMediaOffice/status/2055953520302682178?s=20 [32] https://understandingwar.org/research/middle-east/iran-update-special-report-april-13-2026/ ; https://x.com/KuwaitArmyGHQ/status/2047613443843203195; https://t.me/Extremedistress/861 ; https://t.me/Extremedistress/914 ; https://t.me/Jaysh_AlGhadab/77 ; https://t.me/aishab_alkahf/505 ; https://t.me/Jaysh_AlGhadab/86 ; https://t.me/Jaysh_AlGhadab/121 ; https://t.me/Jaysh_AlGhadab/128 ; https://t.me/awlialdm/346 [33] https://t.me/AbumujahidAlasaf/11 [34] https://t.me/AbumujahidAlasaf/11 [35] https://t.me/Extremedistress/931 ; https://t.me/awlialdm/295 ; https://understandingwar.org/research/middle-east/iran-update-special-report-march-25-2026/ ; https://understandingwar.org/research/middle-east/iran-update-morning-special-report-march-4-2026/ ; https://understandingwar.org/research/middle-east/iran-update-evening-special-report-march-6-2026/
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