A U.S. aircraft carrier transits the Strait of Hormuz in this undated photo. U.S. Central Command said it will begin a naval blockade of all maritime traffic entering and exiting Iranian ports at 10 a.m. Eastern on Monday, following an order from President Donald Trump after weekend talks failed to produce a deal to end the conflict. (Merissa Daley/U.S. Navy)
A U.S. maritime blockade targeting Iranian ports took effect Monday, marking a sharp military escalation as a fragile ceasefire between Washington and Tehran appeared on the brink of collapse.
U.S. Central Command has said its forces would block shipping traffic in and out of Iranian ports starting at 10 a.m. Monday, though details on how the blockade is being enforced remain limited.
With the blockade, U.S. President Donald Trump is applying severe economic pressure on Iran, which has largely restricted shipping through the Strait of Hormuz since the war began in late February.
The closure of the strait, which usually carries about a fifth of the world’s oil, has rattled global markets and sent fuel prices soaring.
The U.S. restrictions appear broad in scope. A U.K. Maritime Trade Operations advisory said the blockade encompasses the entirety of Iran’s coastline, including ports and energy infrastructure, and that neutral vessels currently within Iranian ports have been granted a limited grace period to depart.
In a post on Truth Social, Trump warned that any vessels approaching the blockade would be “immediately ELIMINATED,” adding that the U.S. would use “the same system of kill that we use against the drug dealers on boats at Sea.”
Earlier, U.S. Central Command said the blockade “will be enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas, including all Iranian ports on the Arabian Gulf and Gulf of Oman.”
“CENTCOM forces will not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports,” the statement added.
The tensions continue to test the already fragile ceasefire, which was agreed to last week.
According to The Wall Street Journal, Trump and his advisers are weighing whether to resume limited strikes against Iran in addition to the blockade to help break the stalemate in the Strait of Hormuz.
Trump’s call for a naval blockade came early Sunday after negotiations in Pakistan failed to bring about an end to the U.S. war with Iran.
Maritime traffic in the Strait of Hormuz has remained severely reduced amid ongoing security concerns following attacks on commercial vessels.
Energy prices rose sharply Monday following the failed peace talks and news of the blockade, which could further tighten the global oil supply.
Brent crude, the global oil benchmark, rose 7% to near $102 a barrel, a gain of 40% since the start of the war.
Trump said Sunday that other countries would be involved in the blockade, but as of late Monday morning, it was unclear which ones, if any, would join.
In an interview with the BBC, British Prime Minister Keir Starmer said his government would not join the blockade but will instead continue to focus on getting the strait “fully open.”
The U.K., he added, “is not getting dragged into” war with Iran.
French President Emmanuel Macron said his country will help organize a conference with countries prepared to support a “peaceful multinational mission” aimed at restoring freedom of navigation in the waterway.
“This strictly defensive mission, separate from the warring parties to the conflict, is intended to be deployed as soon as circumstances permit,” Macron said Monday on X.
Australian Prime Minister Anthony Albanese said his country has not received a request to participate in the blockade.
The U.S. and Iran held over 20 hours of high-level talks in Islamabad, but both sides walked away early Sunday, accusing the other of making excessive demands.
Vice President JD Vance, who led the U.S. negotiating team, said the major sticking point was Iran’s failure to provide assurances that it would not seek to develop nuclear weapons.
Iran’s foreign minister, Abbas Araghchi, countered that Tehran had been negotiating “in good faith.”
“But when just inches away from (an) ‘Islamabad MoU,’ we encountered maximalism, shifting goalposts, and blockade. Zero lessons earned,” Araghchi said on X.
An Iranian military spokesperson, meanwhile, warned that ports in the Persian Gulf and Sea of Oman would not be safe if Iranian ports are threatened, according to Iranian state media.
Trump has alternated between suggesting the conflict was nearing completion and that it could be significantly escalated, possibly with the use of U.S. forces who continue to head to the region.
“I predict they come back and they give us everything we want,” Trump said Sunday during a Fox News interview. “And I tell my people, I want everything. I don’t want 90%, I don’t want 95%. I told them I want everything.”
