In less than a day, the Strait of Hormuz closed again. On April 17, Iranian Foreign Minister Abbas Araghchi announced that the passage for commercial vessels was "completely open" — linked to a ceasefire between Israel and Hezbollah. On April 18, the Islamic Revolutionary Guard Corps (IRGC) stated that control over the strait had "returned to its previous state" in response to the continuation of the American blockade of Iranian ports.
What happened between opening and closing
A temporary ceasefire between the US and Iran took effect on April 17 after 49 days of armed conflict. Iran opened the strait but set conditions: only commercial vessels, a route agreed upon with the IRGC along the Iranian coast, and cargo not from "hostile states." According to Iran International, these conditions were part of a Pakistani mediation plan.
Trump thanked Tehran — but in the same post on Truth Social clarified:
"The maritime blockade will remain in full force against Iran — until such time as our deal with Iran is executed 100%."
Donald Trump, Truth Social, April 17, 2026
Iran's side perceived this as a continuation of the conflict. Parliament Speaker Mohammad-Baqer Qalibaf wrote on X: "If the blockade continues — the Strait of Hormuz will not remain open". And it did not.
Why the US blockade is the central point of contention
The American blockade of Iranian ports took effect on April 13 following the collapse of negotiations in Islamabad, where delegations from Washington led by Vance and Tehran failed to reach agreement. CENTCOM stated clearly: the blockade applies to all vessels entering or leaving Iranian ports, regardless of flag. According to Admiral Brad Cooper, American forces have "completely halted maritime trade with Iran." By April 17, the US Navy had turned back at least 21 vessels.
Tehran called the blockade "piracy" and a violation of the ceasefire. The problem is that the ceasefire text, according to NBC News and AP, did not contain a mechanism that would obligate the US to lift the blockade as a precondition for opening the strait — rather than as a consequence of signing the final agreement.
What is at stake for the rest of the world
Before the conflict, approximately 20% of global maritime crude oil transport and 20% of liquefied natural gas passed through the Strait of Hormuz. International Energy Agency head Fatih Birol called the current situation on April 16 "the biggest energy crisis we have ever had."
- The European Commission received a warning from Airports Council International: a shortage of aviation fuel could begin as early as early May.
- According to the IEA, 75% of Europe's aviation fuel imports came from the Middle East via Hormuz — supplies are "approximately six weeks."
- In the US, the average price of gasoline reached $4.11 per gallon, according to AAA.
- Oil approached $100 per barrel following the announcement of the American blockade.
French President Macron and British Prime Minister Starmer held a summit with allies in Paris on April 17. Their plan is to create a "neutral" maritime mission after the conflict ends, without US participation. For now, this is a scenario for after, not for now.
The structure of the trap
The situation looks like constructive ambiguity that suits both sides in different ways. Iran opened the strait — and demonstrated good faith. The strait is closed — and maintains pressure on negotiations. The US preserved the blockade as a tool to compel the final agreement, but it also gives Tehran a reason to backtrack.
Trump stated aboard Air Force One: "Once the deal is signed — the blockade is over". But the deal is not yet signed, negotiation timelines are fluid, and the ceasefire lasts only ten days.
If by the end of the week the US and Iran do not agree on whether lifting the blockade is a precondition or a consequence of the agreement, another cycle of opening-closing the Strait of Hormuz will become nearly inevitable — and then the question of "six weeks of aviation fuel" for Europe will transform from an IEA warning into operational reality.
