The United States Central Command (CENTCOM) began a full blockade of all maritime traffic entering and leaving Iranian ports on Monday, April 13, 2026, at 10:00 AM Eastern Time. The measure aims to cut off Tehran's remaining oil export revenues, estimated at roughly 2 million barrels per day, while leaving the Strait of Hormuz open for other commercial shipping.
Background and Enforcement Details
The blockade was ordered following the collapse of peace talks in Islamabad, Pakistan, under a presidential directive. President Donald Trump announced the decision on Truth Social on April 12, stating the US Navy would “immediately” begin stopping vessels attempting to enter or leave the Strait of Hormuz. Trump accused Iran of collecting illegal tolls from passing ships, ordered mine-clearing operations, and warned that any Iranian forces firing on US vessels or commercial traffic would face “HELL.”
CENTCOM's language was more measured. The command said additional notifications would be issued to commercial mariners before sanctions took effect, instructing all vessels operating in the Gulf of Oman and approaches to the Strait to follow Notices to Mariners and contact US naval forces on bridge-to-bridge Channel 16. The blockade directly responds to Iran's de facto control of the Strait since the outbreak of the US-Israel-Iran war on February 28, 2026—Iran had restricted passage and imposed tolls, paralyzing roughly one-fifth of global oil and liquefied natural gas shipments.
Market Turmoil
Oil markets moved instantly. WTI crude futures surged approximately 5% to above $94 per barrel. Brent crude rose about 6%, climbing back above $100 per barrel. US gasoline wholesale prices also jumped. Equity markets reflected the uncertainty: the Dow Jones Industrial Average fell 246.90 points to 47,669.67, the NYSE Composite dropped 29.54 points to 22,704.96, while the Nasdaq rose 46.79 points to 22,949.69, and the S&P 500 edged up 0.67 points to 6,817.56.
Military and Diplomatic Stakes
Implementing the blockade requires a large-scale naval operation. Analysts note it involves multiple aircraft carrier strike groups, dozens of destroyers and frigates, and support from regional allies. The Strait poses real tactical risks from Iranian anti-ship missiles, drones, fast attack boats, and mines, making the effort high-risk from day one.
Iran's Islamic Revolutionary Guard Corps condemned the move as “an act of piracy” and declared it illegal under international law. Iranian officials warned that “no port in the Persian Gulf or the Gulf of Oman will be safe” if Iranian ports are targeted, reiterating their position that the Strait must be “for everyone or for no one.” Tehran insists diplomacy is the only legitimate way forward.
International reactions were cautious. Several Gulf states, including Oman, and mediators expressed concern over escalation. The UK did not confirm the mine-clearing role attributed to it by Trump. European leaders avoided language suggesting a full closure of the Strait to all traffic.
The Islamabad talks collapsed primarily over Iran's nuclear program and a set of unresolved conditions neither side was willing to concede. A fragile two-week ceasefire was in place leading up to the negotiations.
Trump Warns China
Trump also warned China on April 12 that it would face an immediate 50% tariff if caught arming Iran, as US intelligence reported possible MANPADS deliveries during the ceasefire.
Washington has not announced a definitive end date for the blockade. US officials say the duration depends on Iran's compliance and progress toward a broader diplomatic deal. The legal status of the blockade remains contentious, with debates over whether belligerent rights in an armed conflict apply or whether peacetime international maritime law prevails.