12/ ISW-CTP will provide further analysis on the negotiations and ceasefire in its April 20 Iran Update.

11/ The US Navy has likely forced two Iranian-linked and US-sanctioned vessels to turn around near the blockade line since ISW-CTP's last data cutoff on April 19, according to commercially available shipping data.

10/ US Central Command confirmed that the US Navy has turned back 27 vessels attempting to enter or exit Iranian ports since the start of the blockade.

9/ The Iranian regime shipping subsidiary that operates Touska previously transported 1,000 tons of sodium perchlorate from China to Iran in 2025, according to the Wall Street Journal.

8/ The director of a maritime transparency project, @GordianKnotRay, noted that the Touska traveled to Zhuhai Port in China twice in March. Zhuhai Port is considered a loading port for chemicals, including missile fuel precursor sodium perchlorate, according to the Washington Post.

7/ The Iranian Khatam ol Anbia Central Headquarters spokesperson condemned the US Navy’s seizure of the Iranian-owned cargo ship, Touska, on April 19, describing it as a ceasefire violation.

6/ US President Trump told Bloomberg that it’s “highly unlikely" that he’d extend the ceasefire if Iran and the United States do not reach a deal before the ceasefire ends..

5/ ISW-CTp previously assessed that IRGC Commander Ahmad Vahidi and members of his inner circle, not Ghalibaf, are likely driving decision-making in Tehran, however.

4/ Ghalibaf’s messaging may have been in response to recent criticism from Iranian hardliners about Iran’s participation in negotiations. Ghalibaf may be attempting to secure a ceasefire extension. The ceasefire is set to expire in the evening Washington time on April 22, according to Trump.

3/ Iranian Parliament Speaker Mohammad Bagher Ghalibaf, who was part of the Iranian delegation in the first round of negotiations in Islamabad, defended Iran’s participation in negotiations as a means to secure Iranian objectives in an interview with Iranian state media on April 18.

2/ Iran has yet to confirm whether it will send an Iranian delegation to Islamabad. The Iranian Foreign Affairs Ministry spokesperson stated that Iran is still reviewing the US proposal that Pakistani Army Chief Asim Munir conveyed to Iran during his visit to Tehran last week.

NEW | US President Donald Trump stated that Vice President JD Vance, US Special Envoy to the Middle East Steve Witkoff, and Jared Kushner are “heading over [to Islamabad, Pakistan] now” for a second round of negotiations with Iran. (1/12)

6/ A statement released by Iranian-backed Iraqi militia Kataib Hezbollah on April 18 appears to confirm that IRGC Quds Force Commander Brigadier General Esmail Ghaani discussed preparations for renewed conflict with the US and Israel during his meetings with Iraqi militia leaders in Baghdad.

5/ Incomplete reporting about the damage that the US-Israeli combined force inflicted on Iran’s ballistic missile and drone programs precludes the development of a quantitative assessment about the threat that Iranian missiles and drones still pose.

4/ JD Vance, Steve Witkoff, and Jared Kushner are expected to travel to Islamabad, Pakistan, to engage in negotiations with Iran on April 21. ISW-CTP has not observed any Iranian sources confirming Iran’s participation in the negotiations as of 6:00 PM ET on April 19, however.

3/ US forces seized an Iranian-flagged container ship for the first time during the war. Commercially available shipping data indicates that the US Navy also forced at least three Iranian or Iranian-linked ships to change course toward Iranian ports on April 19.

2/ More Key Takeaways:
Iran is trying to establish a protection racket in the strait by granting priority transit to vessels that pay fees and comply with IRGC protocols to try to consolidate control over the strait. Iran continued to prevent non-Iranian-linked vessels from transiting the strait.

NEW: A US settlement/resolution that enables Iran to control traffic through the strait would represent a major US defeat and set a precedent w/ implications for global trade, given the strait’s role as an energy chokepoint. (1/6)

Iran Update Special Report, April 19, 2026: isw.pub/IranUpdate04...

3/ Ukrainian forces recently advanced in the Kostyantynivka direction. Russian forces recently advanced in Kursk Oblast.

Russian forces launched 236 drones against Ukraine. Ukrainian forces struck the Atlant Aero drone development and production plant in Taganrog, Rostov Oblast.

2/ The USF used a USV-launched interceptor drone to intercept a RU Shahed long-range strike drone for the 1st time & are creating USF naval drone battalions.

RU defense industrial enterprise director criticized how the RU govt’s policies overcooled the economy, hurting import substitution efforts.

NEW: RU forces conducted 4 platoon-sized or smaller mechanized & motorized assaults across the theater in the last 48 hours, but they are unlikely to bolster the RU spring-summer 2026 offensive.

Russian Offensive Campaign Assessment, 4.19.26: isw.pub/UkrWar041926

More Key Takeaways ⬇️(1/3)

6/ The IRGC has continued to prevent traffic through the Strait of Hormuz. The IRGC Navy reportedly forced two oil tankers attempting to transit through the strait to change course. Many vessels that intended to transit through the strait have turned around.

5/ Iran is trying to establish a protection racket in the strait, likely to consolidate the IRGC control of it and gain leverage over the US in negotiations. Iran has reportedly decided to give vessels that pay a “security” fee and adhere to Iranian protocols priority to transit through the strait.

4/ The Iranian negotiating team does not have the authority to independently determine Iran’s negotiating positions. IRGC Commander Major General Ahmad Vahidi and other senior members of the IRGC have consolidated control and wielded significant influence over the negotiations process thus far.

3/ The upcoming talks appear focused on extending the ceasefire, which is set to expire on April 22. Iranian sources familiar with the negotiations stated that Iran expects that the ceasefire will be extended and that additional talks will occur if the negotiations on April 21 go well.

2/ US Special Envoy to the Middle East Steve Witkoff and Jared Kushner will attend the talks. Iran’s negotiating delegation is expected to include Foreign Minister Abbas Araghchi and Parliament Speaker Mohammad Bagher Ghalibaf.

NEW: The Iranian political officials who will reportedly negotiate with the United States in Islamabad, Pakistan, on April 21 neither have the authority to independently determine Iran’s negotiating positions nor are driving decision-making in Tehran.

More Key Takeaways ⬇️ (1/6)

Iran Update Special Report, April 18, 2026 Regime institutions aligned with Vahidi are presenting a cohesive front against Araghchi and in support of the IRGC.

5/ The US Navy’s blockade of Iranian ports remains in place as of April 18. US CENTCOM said that it forced two ships to turn around and return to Iran between April 17 and 18.

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4/ The IRGC attacked several commercial vessels and halted traffic in the Strait of Hormuz on April 18, likely in order to both gain leverage over the United States

3/ The IRGC’s consolidation of control over Iranian decision-making indicates that the Iranian political officials currently negotiating with the United States do not have the authority to independently determine Iran’s negotiating positions.