The United States military issued a warning Monday that it will be enforcing a blockade of Iranian ports on the Gulf of Oman — east of the Strait of Hormuz — as ceasefire negotiations with Iran broke down over the weekend, U.S. Central Command said in a notice to seafarers.
The notice said the blockade would begin at 10 a.m. eastern, following a proclamation from U.S. President Donald Trump. The Gulf of Oman is a strategic body of water in the Arabian Sea, which lies just east of the Strait of Hormuz, which Iran has been blocking to most international shipping traffic for weeks.
“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,” the U.S. military notice said.
Meanwhile, NATO allies, including Britain and France, said they would not be drawn into the conflict by taking part in the blockade.
“We’re not supporting the blockade,” British Prime Minister Keir Starmer told the BBC.
“My decision has been very clearly that whatever the pressure, and there’s been some considerable pressure, we’re not getting dragged into the war,” he said.
The U.S. said it will “not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports.”
Get breaking National news
Get breaking Canada news delivered to your inbox as it happens so you won’t miss a trending story.
“Any vessel entering or departing the blockaded area without authorization is subject to interception, diversion, and capture,” the note said.
The blockade “encompasses the entirety of the Iranian coastline to include but not limited to ports and oil terminals,” the note said, adding that humanitarian shipments including food, medical supplies and other essential goods would be permitted, subject to inspection.
Tehran has threatened to retaliate against ports of its Gulf neighbours after weekend talks failed to reach a deal to end the war, leaving a ceasefire in jeopardy.
Oil prices surged when trade reopened on Monday, with no sign of a swift reopening of the Strait of Hormuz to ease the worst-ever disruption in supplies.
Since the war started, Iran has effectively shut the strait to all vessels except its own, saying ships would only be allowed through under Iranian control and subject to a fee. Trump said he would now block Iran’s ships too, and any vessels that paid Iran a toll.
Two Iranian-linked tankers, the Aurora and New Future, laden with oil products and diesel, left the strait on Monday shortly before the U.S. blockade was due to take effect, according to data from provider LSEG.
An Iranian military spokesperson, quoted by state media, said any U.S. restrictions on vessels in international waters would be illegal and amount to “piracy.” If Iranian ports were threatened, no port in the Gulf or Gulf of Oman would remain secure, the spokesperson said.
Earlier, Iran’s Revolutionary Guards said any military vessels approaching the strait would be considered to have violated the ceasefire.
On Sunday, Trump posted on social media: “No one who pays an illegal toll will have safe passage on the high seas,” adding, “Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!”
— with files from Reuters
© 2026 Global News, a division of Corus Entertainment Inc.
