Iran Update, September 26, 2025

Information Cutoff: 2:00 PM ET

The  Critical Threats Project (CTP) at the American Enterprise Institute and the Institute for the Study of War (ISW) publish the Iran Update, which provides insights into Iranian and Iranian-sponsored activities that undermine regional stability and threaten US forces and interests. CTP-ISW publishes the Iran Update daily.

Click here to see CTP and ISW’s interactive map of assessed control of terrain in Syria, and here to see CTP and ISW’s interactive map of Israeli ground operations. The Syria map is updated daily alongside the static Syria maps in this report. CTP-ISW ended daily maps of Israeli ground operations in February 2025.

Click here to see ISW-CTP's interactive map showing the total strikes in Iran during the Israel-Iran War, as well as an interactive timelapse showing the strikes day-by-day.

The E3 (the United Kingdom, France, and Germany) will reimpose UN Security Council (UNSC) sanctions on Iran on September 27 despite a last-ditch Iranian effort to delay the snapback mechanism. A UK-based media outlet reported on September 26 that Iran offered to immediately grant International Atomic Energy Agency (IAEA) inspectors full access to the Natanz Nuclear Facility. Iran, in return, called for the UNSC to adopt a Russian-Chinese resolution to extend the snapback mechanism’s deadline by six months.[i] The UNSC rejected the Russian-Chinese resolution in a vote on September 26, which means the UNSC sanctions will automatically be reimposed on September 27.[ii] The E3 offered in July 2025 to extend the snapback mechanism’s deadline if Iran fully cooperated with the IAEA, resumed nuclear talks with the United States, and accounted for its 60 percent enriched uranium stockpile.[iii] Iran failed to meet the E3’s conditions.

Iran has continued to expand its nuclear infrastructure at the Mount Kolang Gaz La facility in Esfahan Province, which was not damaged or targeted during the Israel–Iran War in June 2025.[iv] The Washington Post, citing satellite imagery, reported on September 26 that Iran has made key changes at the site since the war.[v]

• Security perimeter: Iran completed construction on roughly 4,000 feet of wall on the western edge and graded a parallel road, which brings the enclosure close to completion.
• Tunnel entrance: Iran reinforced one eastern entrance with dirt and rock to prevent damage or potential collapse in future airstrikes.
• Excavation spoil: The pile of rock and soil outside the eastern tunnels has modestly increased, indicating continued tunneling inside the mountain.

Unspecified analysts told the Washington Post that the facility’s underground halls may be 260 to 330 feet deep, which is deeper than the underground halls at Iran’s Fordow Fuel Enrichment Plant.[vi] The depth of the facility’s underground halls has fueled suspicions that the site could serve not only as a centrifuge assembly plant, as Iran announced in 2020, but also as a covert enrichment facility or secure storage for near-weapons-grade uranium.[vii] The Institute for Science and International Security reported in April 2025 that Iran had already begun building a security wall with new roads and space for fences, lights, and cameras at the facility.[viii] The institute’s report noted that the facility could house an advanced centrifuge assembly plant or potentially a small undeclared enrichment plant.[ix] The IAEA has never inspected the Mount Kolang Gaz La facility, which illustrates the limitations that the IAEA faces in obtaining a complete picture of Iran‘s nuclear program. Iran also barred IAEA inspectors from accessing the site’s tunnels in April 2025 and told the agency that “it is none of [their] business.”[x]

Iran is attempting to exploit anti-Israel sentiments in Saudi Arabia in order to protect Hezbollah from its looming disarmament. Iran’s attempts to exploit anti-Israel sentiment in the Saudi government will most likely fail due to Iran’s long history of attacking Saudi Arabia with proxies and partners trained by Hezbollah.  Iranian officials appear to have grown increasingly concerned about Hezbollah's ability to retain its weapons amid the Lebanese state’s current efforts to disarm the group following Supreme National Security Council Secretary Ali Larijani’s trip to Riyadh on September 16.[xi]  that Hezbollah’s disarmament was one of the “main topics” of Larijani’s visit and that Larijani attempted to convince Riyadh that Hezbollah’s disarmament would benefit neither Lebanon nor the region.[xii] Saudi Arabia has positioned itself in recent months as one of the principal regional powers supporting the Lebanese state’s efforts to disarm Hezbollah. [xiii] Larijani urged Hezbollah Secretary General Naim Qassem to reach out and show “goodwill” to Saudi Arabia after his trip,  Qassem—in acquiescence to Larijani's request—called on Saudi Arabia to “open a new page” with Hezbollah during a speech on September 19.[xv] Qassem argued that both parties have a common enemy in Israel.[xvi]

Qassem’s reasoning is consistent with Iranian diplomatic efforts and rhetoric that have attempted to exploit regional anti-Israel sentiments in the wake of Israel's strikes on Doha, Qatar, on September 9.[xvii] Iran has aimed these efforts at Gulf states, such as Saudi Arabia, and has called for Arab, Islamic, and international responses since Israel's strikes in Doha.[xviii] Iranian officials have framed Israel’s strikes as an opportunity to unite regional powers—particularly the Gulf states—in an anti-Israel, anti-United States regional coalition.[xix]

Such an Iranian effort to exploit anti-Israel sentiments in Saudi Arabia is highly unlikely to weaken Saudi support for Hezbollah’s disarmament. Hezbollah has trained several Iranian proxy and partner groups—including Kataib Hezbollah in Iraq and other Iraqi militias and the Houthis—that have targeted Saudi Arabia. Saudi Arabia, in addition to other Gulf states, has promised significant economic aid to Lebanon that is contingent on Hezbollah’s disarmament, likely as an economic incentive to pressure the Lebanese government to implement its disarmament plan.[xx] Saudi Arabia is unlikely to ease pressure on the partner of its regional rival, Iran, based on shared anti-Israel sentiment alone.

Key Takeaways

• Snapback Sanctions: The E3 (the United Kingdom, France, and Germany) will reimpose UN Security Council (UNSC) sanctions on Iran on September 27 despite a last-ditch Iranian effort to delay the snapback mechanism. The E3 rejected Iran’s offer to immediately grant International Atomic Energy Agency (IAEA) inspectors full access to the Natanz Nuclear Facility in return for the UNSC adopting a Russian-Chinese resolution to extend the snapback mechanism’s deadline by six months.
• Iranian Nuclear Program: Iran has continued to expand its nuclear infrastructure at the Mount Kolang Gaz La facility in Esfahan Province, which was not damaged or targeted during the Israel-Iran War in June 2025. Iran has made significant changes to the site’s security perimeter and tunnel entrance since the war, and increased excavation spoil outside the tunnel entrances suggests increased tunneling at the site.
• Hezbollah-Saudi Arabia Relations: Iran is attempting to exploit anti-Israel sentiments in Saudi Arabia in order to protect Hezbollah from its looming disarmament. Iran’s attempts to exploit anti-Israel sentiment in the Saudi government will most likely fail due in part to Iran’s long history of attacking Saudi Arabia with proxies and partners trained by Hezbollah.

Iran

Khatam ol Anbia Air Defense Headquarters Commander Brigadier General Ali Reza Sabahi Fard inspected an unspecified air defense site in northwestern Iran on September 26.[xxi] Sabahi Fard commended the Islamic Revolutionary Guards Corps (IRGC) and Artesh on their performance during the Israel-Iran War in June 2025. Sabahi Fard noted that Iran’s air defense is at its “highest level” of combat capability and defense readiness. Israel destroyed a significant number of Iranian air defense systems and radars throughout the war to establish air superiority over Iran.[xxii]

Iraq

Nothing significant to report.

Syria

Syria and Israel’s security negotiations have reportedly stalled due to Israel’s demand for a humanitarian corridor between Israel and Suwayda City in Syria, according to unspecified sources speaking to Reuters.[xxiii] Syria and Israel have engaged in negotiations since mid-August 2025 over the demilitarization of southwestern Syria, Israeli withdrawal from Syrian territory captured after the Assad regime’s fall, and protection of Suwayda Province’s Druze population.[xxiv] Syria and Israel were reportedly close to reaching a “de-escalation” agreement until Israel reintroduced its demands for a humanitarian corridor between Israel and Suwayda City, which has stalled the negotiations.[xxv]  Israel previously proposed to establish a humanitarian aid corridor spanning over 40 miles from the Israeli border to Suwayda City in August 2025, which Syrian officials rejected.[xxvi] Syrian officials have continuously argued that such a corridor would violate Syrian sovereignty.[xxvii]  

Arabian Peninsula

Commercially available satellite imagery captured on September 26 confirmed that the Israeli airstrikes on September 25 damaged six Houthi sites across Sanaa City, including five command and control sites and one weapons depot.[xxviii] The Israel Defense Forces (IDF) Air Force confirmed on September 25 that it struck five Houthi command sites and two weapons depots in Sanaa City in response to the recent Houthi drone and missile attacks targeting Israel.[xxix] The IDF stated that the strikes targeted the Houthi General Staff Headquarters, facilities affiliated with the Houthi Security and Intelligence Service (SIS), the Houthi Propaganda Department, and additional military complexes in Sanaa City.[xxx] An IDF strike heavily damaged a Houthi SIS facility in Wahdah District, according to commercially available satellite imagery. Houthi SIS sources and Mohammad al Basha, a Yemen-focused analyst, claimed that this strike targeted an SIS facility that housed political prisoners detained by the Houthis.[xxxi] The IAF airstrikes also damaged two other Houthi SIS facilities in Bani Harith District and in Old City District, as well as seven buildings owned by the Houthi-controlled Yemeni General Corporation for Social Security, according to Basha and commercially available satellite imagery.[xxxii] Commercially available satellite imagery also confirmed that the IAF airstrikes damaged buildings in the east wing of the Presidential Palace complex, which reportedly houses Houthi command sites and likely weapons depots. The IAF strikes also damaged a warehouse near Dhabhan Power Station, which likely served as a weapons depot.[xxxiii]

The Houthis launched a ballistic missile on September 25 targeting “several sensitive” sites in the Tel Aviv-Jaffa area, central Israel, following Israeli airstrikes on Houthi sites in Sanaa City on September 25.[xxxiv] The IDF Air Force intercepted the missile.[xxxv] The Houthis have launched hundreds of drones and ballistic missiles targeting Israel since the Houthis began their campaign to enforce an economic “blockade” on Israel in October 2023.[xxxvi]

Palestinian Territories and Lebanon

See topline section.