The US Central Command said the US Navy began enforcing a blockade on all maritime traffic entering and leaving Iranian ports at 10 a.m. ET on April 13, 2026. The operation is aimed at ports along the Persian Gulf and Gulf of Oman and is designed to cut off Tehran’s remaining oil export income while still allowing commercial shipping bound for non-Iranian ports to pass through the Strait of Hormuz.
Washington targets Tehran’s oil lifeline
According to the US, the order followed the collapse of peace talks in Islamabad and was issued under presidential direction. Washington argues that since the outbreak of the US-Israel-Iran war on February 28, 2026, Iran has effectively tightened control over transit through the Strait of Hormuz, restricting movement and charging vessels passing through the route. That disruption has affected roughly one-fifth of global oil and liquefied natural gas shipments. The latest blockade is intended to pressure Iran by targeting what had previously been estimated at around 2 million barrels per day in oil exports.
President Donald Trump said on April 12 that the US Navy would move “immediately” to stop ships attempting to enter or leave the relevant zone, while also referencing mine-clearing operations and warning Iran against firing on US or commercial vessels. CENTCOM’s formal language was more measured, saying additional notices would be issued to merchant mariners and instructing vessels operating in the Gulf of Oman and Strait of Hormuz to monitor navigation broadcasts and contact US naval forces on bridge-to-bridge channel 16.
Oil surges as markets absorb escalation risk
Energy markets reacted almost instantly. WTI crude climbed about 5% to above $94 a barrel, while Brent rose about 6% and moved back above $100. Wholesale gasoline prices also advanced. US equities reflected a more cautious mood: the Dow Jones Industrial Average fell 246.90 points, the NYSE Composite slipped, while the Nasdaq managed a modest gain and the S&P 500 was little changed.
Analysts note that enforcing a blockade of this scale would require a major naval commitment, including multiple carrier strike groups, dozens of destroyers and frigates, and support from regional allies. The Strait itself presents serious tactical vulnerabilities, given the risk from anti-ship missiles, drones, fast attack boats, and naval mines, making the operation high-risk from the outset.
Iran condemns move as unlawful
Iran’s Islamic Revolutionary Guard Corps denounced the measure as an act of piracy and argued that it violates international law. Iranian officials warned that if Iranian ports were targeted, no port in the Persian Gulf or Gulf of Oman would remain safe. Tehran also repeated its long-standing position that the Strait of Hormuz must either remain open to everyone or to no one, while insisting diplomacy is the only legitimate path forward.
International reactions have been restrained but uneasy. Several Gulf states and mediators, including Oman, have raised concerns about further escalation. The UK did not confirm the mine-clearing role referenced by Trump, and European leaders avoided any interpretation that could imply support for a full closure of the strait. Washington has not announced a fixed end date for the blockade, saying its duration will depend on Iranian compliance and progress toward a broader diplomatic agreement. The legal basis of the blockade also remains contested under international law.