The U.S. military said Sunday it would begin a blockade of all Iranian ports within hours, after peace talks in Pakistan collapsed with Washington blaming the Islamic republic's refusal to abandon its nuclear ambitions.
The announcement came despite a ceasefire agreed on Wednesday aimed at pausing the six-week war until April 22, with tensions centered on whether the United States can force Iran to reopen the strategic Strait of Hormuz, another of its key demands in the stalled negotiations.
"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," U.S. Central Command said in a statement, adding that it would begin at 1400 GMT on Monday.
The statement said U.S. forces would not impede vessels transiting the Strait of Hormuz to and from non-Iranian ports, and that further instructions for mariners would be forthcoming.
Iran's Revolutionary Guards had earlier warned they had full control of traffic through Hormuz and would trap any challenger "in a deadly vortex."
In a lengthy social media post, U.S. president Donald Trump said his goal was to clear the strait of mines and reopen it to all shipping, but that Iran must not be allowed to profit from controlling the waterway.
"Effective immediately, the United States Navy, the Finest in the World, will begin the process of BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz," Trump said. "Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!"
Iran's parliament speaker Mohammad Bagher Ghalibaf, who led Tehran's delegation in Pakistan, said on returning home that the country would "not bow to any threats" from Washington, while navy chief Shahram Irani called Trump's blockade threat "ridiculous."
Tehran has already been restricting traffic through the strait — a key route for global oil and gas shipments — while allowing some vessels serving friendly countries such as China to pass. There have been unconfirmed reports it plans to charge tolls.
The U.S. military said Saturday that two Navy warships had transited through the strait to begin clearing it of mines and ensure it was a "safe pathway" for tankers, a claim Tehran denied.
Iran's Fars news agency reported Sunday that two Pakistani-flagged oil tankers bound for the strait had turned back.
'Final and best offer'
The collapse of the talks rattled an already tense region and raised fears of renewed fighting.
In a later Fox News interview, Trump again threatened Iran's energy infrastructure and warned he would impose a 50-percent tariff on Chinese imports if Beijing tried to help Iran's military.
The U.S. blockade appeared to be triggered by the failure of talks in Islamabad on ending the war.
The U.S. delegation — led by Vice President JD Vance, special envoy Steve Witkoff and Trump's son-in-law Jared Kushner — was frustrated by Iran's refusal to give up what it called its right to a nuclear program.
"I have always said, right from the beginning, and many years ago, IRAN WILL NEVER HAVE A NUCLEAR WEAPON!" Trump said.
After the talks — the highest-level meeting between the sides since the 1979 Islamic revolution — Vance said Washington had made Tehran its "final and best offer," adding: "We'll see if the Iranians accept it."
Iranian lawmaker Mahmoud Nabavian, who also attended the negotiations, said on X the excessive U.S. demands included "a joint share with Iran in the benefits of the Strait of Hormuz" as well as the removal of the country's 60-percent enriched uranium.
Iran's Foreign Minister Abbas Araghchi said in a post on X that Tehran had been just "inches away" from a deal with Washington but were confronted with "maximalism, shifting goalposts, and blockade."
The failure of the talks will raise fears that renewed fighting could drive energy prices higher and further damage shipping and oil and gas facilities.
Shortly after trading began, a barrel of West Texas Intermediate (WTI) for May delivery rose around eight percent to $104.50, while June delivery of international benchmark Brent rose seven percent to $102.
Pakistan urged both sides to keep observing the temporary truce.
But concern has grown that the ceasefire could collapse, in part because of continued Israeli strikes in Lebanon, where Iran insists the truce also applies.
Lebanese and Israeli officials are due to hold talks in Washington on Tuesday.
Tamara, an 18-year-old cashier in Beirut, said focus should remain on Lebanon, where Israeli strikes killed more than 350 people on Wednesday.
"We can't say the war has stopped because there are talks," she said.
"We mustn't forget the massacre that happened."
