US blockade of Iranian ports to start as Trump threatens to hit infrastructure

The US military announced it will begin a blockade of all Iranian ports on Monday, tempering President Donald Trump’s earlier vow to entirely block the strategic Strait of Hormuz as early reports indicated that ships had stopped crossing the waterway.

The move came after marathon US-Iran ceasefire talks in Pakistan ended without an agreement, and it set the stage for a showdown. Iranian leaders vowed to counter the blockade.

US Central Command announced the blockade would involve all Iranian ports, beginning on Monday, to be “enforced impartially against vessels of all nations”.

It would still allow ships travelling between non-Iranian ports to transit the strait, a step down from the president’s earlier threat to blockade the entire waterway.

The announcement of the blockade halted the limited ship traffic that resumed in the strait since the ceasefire, said an early report from Lloyd’s List intelligence. Marine trackers say over 40 commercial ships have crossed since the start of the ceasefire, down from roughly 100 to 135 vessel passages per day before the war.

Later on Sunday, Mr Trump extended his feud over the war with Pope Leo XIV, lashing out in a Truth Social post that called the Catholic leader “terrible on foreign policy”. The extraordinary broadside came after Leo denounced the war and demanded that political leaders stop and negotiate peace.

The blockage is likely intended to add pressure on Iran, which has exported millions of barrels of oil since the war began, much of it likely carried by so-called “dark” transits that evade western government sanctions and oversight.

Mr Trump also hopes to undercut Iran’s control over the Strait of Hormuz after demanding that it reopen the waterway where 20% of global oil transited before fighting began. A US blockade could further rattle global energy markets.

Oil prices rose in early market trading after the blockade announcement.

A chorus of top-ranking Iranian officials threatened retaliation. Mohsen Rezaei, a military adviser and a former Revolutionary Guard Commander, wrote on X that the country’s armed forces had “major untouched levers” to counter a Hormuz blockade. He said Iran would not be coerced by “tweets and imaginary plans”.

Iranian parliament speaker, Mohammad Bagher Qalibaf, who led Iran’s side in the talks, addressed Mr Trump in a statement on his return to Iran: “If you fight, we will fight.”

Iran’s Revolutionary Guard later said the strait remained under Iran’s “full control” and was open for non-military vessels, but military ones would get a “forceful response”, two semi-official Iranian news agencies reported.

During the 21-hour talks this weekend in Pakistan, the US military said two destroyers had transited the strait ahead of mine-clearing work, a first since the war began. Iran denied it.

The face-to-face talks that ended early on Sunday were the highest-level negotiations between the long-time rivals since the 1979 Islamic Revolution.

Mr Trump said Tehran’s nuclear ambitions were the core reason for the talks’ failure. In comments to Fox News, he again threatened to strike civilian infrastructure if it did not give up its nuclear programme.

“In one half of a day they wouldn’t have one bridge standing, they wouldn’t have one electric generating plant standing, and they’re back in the stone ages,” Mr Trump said.

Vice president JD Vance, who led the US side in the talks, said Washington would need “an affirmative commitment that they will not seek a nuclear weapon”.

Iranian officials said talks fell apart over two or three key issues, blaming what they called US overreach.

Neither Iran nor the US indicated what will happen after the ceasefire expires on April 22.

Pakistani foreign minister Ishaq Dar said his country will try to facilitate a new dialogue in the coming days. Iran said it was open to continuing dialogue, state-run IRNA news agency reported.