Iran reimposes restrictions on Strait of Hormuz over US blockade: What to know

Iran has said it is reinstating strict controls over the Strait of Hormuz, reversing an earlier move to ease transit as tensions with the United States escalate over an ongoing naval blockade.

Iran’s central military command said on Saturday it would return to “strict management” of the strategic waterway, accusing Washington of violating commitments by maintaining its naval blockade on vessels to and from Iranian ports.

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In a statement aired on state television, officials said the decision followed what they described as the US failing to uphold terms linked to ongoing negotiations.

“The situation in the Strait of Hormuz will remain strictly controlled until the United States restores freedom of movement for all vessels visiting Iran,” the statement said.

Trump signals ceasefire uncertainty

US President Donald Trump said he may not extend a tentative ceasefire with Iran if talks fail to produce an agreement by Wednesday, raising the possibility of renewed military escalation.

He also reiterated that the US naval blockade would remain in place until a broader deal is reached, including on Iran’s nuclear programme.

"If you don't have a deal by Wednesday when the ceasefire ends, will you extend the ceasefire?"@POTUS: "I don't know. Maybe I won't extend it — but the blockade is going to remain... Unfortunately, we'll have to start dropping bombs again." pic.twitter.com/rhC6ATfezT

— Rapid Response 47 (@RapidResponse47) April 18, 2026

Shipping continues despite tensions

Despite the renewed restrictions, maritime tracking data from MarineTraffic indicates vessels are still transiting the Strait of Hormuz, including tankers carrying oil, LPG and chemicals.

The U.S. naval blockade continues... pic.twitter.com/EBvglrf6FA

— U.S. Central Command (@CENTCOM) April 17, 2026

According to CNN, four tankers reportedly crossed the waterway on Saturday morning heading toward the Gulf of Oman, with some linked to sanctioned shipping networks, according to monitoring data.

US Central Command said earlier that 21 ships have been turned back to Iran since the blockade began on April 13.

Guided-missile destroyer USS Rafael Peralta (DDG 115) directs a merchant vessel to return to an Iranian port as it enforces the U.S. blockade, April 17.

Since commencement of the blockade, 19 ships have complied with direction from U.S. forces to turn around and return to Iran.… pic.twitter.com/v4dhGw8wUH

— U.S. Central Command (@CENTCOM) April 17, 2026

First cruise ship transits since conflict began

In a notable development, the cruise ship Celestyal Discovery has become the first passenger vessel to transit the Strait of Hormuz since the start of the conflict.

The Malta-flagged vessel departed Dubai on April 17 after remaining docked for around 47 days, having first arrived in early March. According to MarineTraffic data, it crossed the Strait of Hormuz and is now heading toward Muscat, Oman, with an estimated arrival on April 18. Reports indicate the ship is currently sailing without passengers.

First cruise ship transits Strait of Hormuz since conflict began

The cruise ship Celestyal Discovery has become the first passenger vessel to transit the Strait of Hormuz since the start of the conflict. The Malta-flagged vessel departed Dubai on 17 April after remaining docked… pic.twitter.com/3wR1P6Lc6G

— MarineTraffic (@MarineTraffic) April 17, 2026

Competing claims over access and control

Iran had earlier signalled the strait was “completely open” during the ceasefire window, while also warning that access would depend on compliance with Iranian conditions, including transit approvals.

Parliament Speaker Mohammad Bagher Ghalibaf warned the strait would not remain open if US pressure continues, saying movement would be limited to designated routes under Iranian authorisation.

Talks and rising uncertainty

Diplomatic discussions remain fragile, with both sides signalling possible negotiations while maintaining pressure on maritime access and sanctions enforcement.

Analysts warn the competing claims over the Strait of Hormuz—through which a significant share of global oil flows—continue to heighten uncertainty in energy markets and global shipping routes.