[ANALYSIS] Iran War Day 45: Countdown to the US' Hormuz Blockade at 15:00BST/10:00EDT

OVERVIEW

• US-Iran talks in Pakistan ended without agreement after 21 hours, with the US leaving a “final and best offer”.
• Disagreements centred on nuclear commitments and the Strait of Hormuz.
• US announced a blockade of Iranian ports, which will begin on April 13 at 17:00 Israeli time (15:00BST/10:00EDT).
• Reports indicated the US is weighing resuming limited strikes alongside the blockade, while leaving the door open for further talks.
• Iran warned that the approach of military vessels toward the Strait of Hormuz is a breach of the ceasefire, while sources threatened the Bab al-Mandab Strait should Trump take action in the Strait of Hormuz.
• It was also reported that the door remains open to a diplomatic solution with Iran, and a second round of talks could be held within days.
• Ceasefire remains in place but under strain, with Israel and Lebanon's hostilities continuing.

WEEKEND TALKS

• The US delegation, led by US Vice President Vance, returned to the US without an agreement after 21 hours of talks.
• US and Iranian delegations have reportedly agreed to hold another round of talks after their recent meeting, with the time and venue to be decided later, Pakistani press reported.

US

• Vance said the US sought an affirmative commitment that Iran would not seek a nuclear weapon or the tools to quickly achieve one.
• Vance said the US left behind a “final and best offer”.
• US President Trump said most points were agreed in talks except nuclear, which he described as the only issue that matters.
• Trump said Iran is unwilling to give up nuclear ambitions and reiterated that Iran will never have a nuclear weapon.

IRAN

• Iranian Foreign Ministry spokesperson Baqaei said success depended on the US refraining from excessive and unlawful demands and negotiating in good faith.
• Iranian reporting said there was disagreement on several issues and that the US demanded through negotiations what it could not obtain through war.
• Iran’s Foreign Ministry said agreement was reached on a number of points, but differences remained on two key issues, including the Strait of Hormuz and nuclear rights.
• Iranian Foreign Minister Araghchi said talks were held in good faith but encountered maximalism, shifting goalposts and blockade pressure.
• Iranian state media said the US made extravagant demands and that the Strait remains a key point of disagreement.
• Iranian state media said talks would continue, while stressing Iran is in no hurry for negotiations.

US BLOCKADE

• US President Trump said the US Navy will begin the process of blockading ships entering or leaving Iranian ports.
• US Central Command said the blockade will begin April 13 at 17:00 Israeli time (15:00BST/10:00EDT).
• The US stated the blockade would not impede vessels transiting the Strait of Hormuz to or from non-Iranian ports.
• Trump said the US is “fully locked and loaded” and warned Iran against targeting US or commercial vessels.
• Trump said the Strait will be cleaned out and expects global support, while stating oil and gas prices will eventually fall.
• White House officials said doubts remain about reopening the Strait of Hormuz in the near term.
• Reports indicated the US is weighing resuming limited strikes alongside the blockade, while leaving the door open for further talks.

IRANIAN WARNING

• Iranian officials said the US blockade threat will have no effect on Iran.
• Iran stated it will maintain its military gains and is not rushing negotiations.
• Iranian Parliamentary Speaker Ghalibaf criticised the blockade and referenced potential energy price impacts.
• IRGC warned that the approach of military vessels toward the Strait of Hormuz is a breach of the ceasefire, IRNA reported.
• Tasnim Agency reports, citing sources, that US President Trump will lose the Bab al-Mandab Strait should he decide to take action against the Strait of Hormuz.
• Iranian armed forces said if Iran’s ports are threatened, then "no port in the Persian Gulf and Oman Sea will be safe", IRIB News reported.

SATURDAY TRANSIT

• US Navy warships transited the Strait of Hormuz on Saturday (11 April), marking the first such crossing since the war with Iran began.
• The move came during US-Iran peace talks in Islamabad under a two-week ceasefire framework.
• Iranian officials denied that any US vessels entered the strait. Iranian reporting suggested at least one US destroyer turned back after warnings and UAV engagement.
• US officials rejected these Iranian claims, stating the ships entered the Persian Gulf and returned as planned, suggesting the ships completed their brief mission inside the Gulf and headed back to the Arabian Sea, rather than "turning back" in retreat as Iran claimed.

ANALYST THOUGHTS

• Analysts describe the 13 April US naval blockade as a high-stakes “economic strangulation” strategy aimed at forcing a breakthrough in stalled US-Iran negotiations, targeting Iran’s ~2mln bpd oil exports to constrain funding of military operations, while also seeking to remove Tehran’s leverage over the Strait of Hormuz by asserting US-led control over maritime access, and ending what Washington views as “illegal tolls” on shipping.
• Oil markets have reacted, with crude benchmarks moving above USD 100/bbl, while some analysts warn of upside risks towards USD 140–150/bbl if escalation continues.
• Broader macro risks centre on a potential “triple shock” scenario—energy shortages, food insecurity, and slower global growth—with Europe seen as particularly exposed given LNG supply constraints.
• A full blockade is viewed as potentially constituting an act of war, raising the likelihood of Iranian retaliation against US assets or regional infrastructure.
• Sustainability of the operation is questioned, with a prolonged naval blockade seen as resource-intensive and difficult to maintain over time.
• Legal grounds remain contested under international maritime law, given that the US does not have sole authority over transit through the Strait of Hormuz.
• Diplomatic risks persist amid limited allied participation and potential friction with China and India, particularly due to the disruption of energy flows and “dark” shipping routes.