US Navy to enforce blockade, Trump says after condemning Iran for blocking waterway and complaining no agreement reached in Islamabad.

President Donald Trump says the United States Navy will begin blockading the Strait of Hormuz “immediately” after peace talks between the US and Iran in Pakistan ended without an agreement.

Trump, in a social media post on Sunday, accused Iran of “extortion” and said the US Navy would also hunt down and interdict ships in international waters that have paid Iran a toll to traverse the strait. He said US forces will also begin clearing mines that he says Iran placed in the strait.

“So, there you have it, the meeting went well, most points were agreed to, but the only point that really mattered, NUCLEAR, was not,” Trump said. “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.”

Iran has essentially taken control over the Strait of Hormuz, a vital chokepoint for the global energy market, since the US and Israel launched a war on Iran on February 28.

Iran’s Islamic Revolutionary Guard Corps (IRGC) warned on Sunday that civilian vessels can cross the strait in compliance with “specific regulations”, but that military vessels approaching the strait would be considered in violation of the ceasefire and “dealt with severely”.

Traffic through the narrow strait has slowed to a trickle, nearly paralysing about one-fifth of the world’s oil and liquefied natural gas shipments and sending shock waves through the global economy.

Trump’s comments have raised concerns about the status of the fragile two-week ceasefire.

“These two posts by the US president are very bombastic, very long, very detailed, and seem to be filled with a great deal of frustration,” Al Jazeera correspondent Zein Basravi said from Dubai in the United Arab Emirates.

“There are no doubt alarm bells ringing here in the GCC [Gulf Cooperation Council] for countries that were hoping this ceasefire would extend beyond those two weeks and become a consistent, long-term negotiated peace that could perhaps lead to different relationships forming in the region, but certainly to an end to the violence we see.”

Mediators have urged both parties to prioritise diplomacy and avoid a return to fighting.

“I urge that the ceasefire be extended and talks continue,” Oman’s Foreign Minister Badr Albusaidi said in a social media post on Sunday. “Success may require everyone to make painful concessions, but this is nothing as compared to the pain of failure and war.” 

Iran has denied US claims that two of its warships recently passed through the strait for mine-clearing operations, warning that any military vessels seeking to do so would receive a “strong response”. Trump called Iran’s control over the waterway “world extortion” in his social media post and added that any Iranian forces who fire at US forces or “peaceful vessels” would be “BLOWN TO HELL”.

He added that the blockade would involve unspecified “other countries”, and he would not allow Iran to benefit from the closure of the strait. Trump also stated in his social media post that the US Navy would interdict “every vessel in International Waters that has paid a toll to Iran”.

“We’re not going to let Iran make money on selling oil to people that they like,” Trump told Fox News in an interview later on Sunday. “It’s going to be all or none, and that’s the way it is.”

He added that the United Kingdom and “a couple of other countries” are sending minesweeper vessels to aid the US effort, an assertion that has not been confirmed by the British government.

Democratic lawmakers in the US have criticised Trump’s comments.

“I don’t understand how blockading the strait is somehow going to push the Iranians into opening it,” Senator Mark Warner, a Democrat, said during an interview with CNN.

“I don’t see the connection there,” he added.

Iran has continued to send its own ships through the strait since the war began and has allowed a handful of vessels from other countries to pass through. Iranian officials have also discussed setting up a toll system after the fighting ends, under which users would pay Iran a fee to cross the strait.

“Iran knows that controlling the Strait of Hormuz is still their main leverage,” Al Jazeera correspondent Ali Hashem reported from the Iranian capital of Tehran. “The higher the tensions, the more prices surge, and this affects the global economy.”