Donald Trump has declared the US will blockade the Strait of Hormuz after the collapse of peace talks with Iran.

The president resumed his bombastic threats just hours after negotiations in Islamabad failed, warning that the US military was ‘locked and loaded to finish Iran’.

Delegations from Washington and Tehran – including vice president JD Vance and Iranian foreign minister Abbas Araghchi – had been locked in crucial negotiations that insiders said were marred by mood swings and tense exchanges.

But Vance announced the talks, which aimed to bring an end to six weeks of costly warfare and to find a solution to Iran’s closure of the shipping lane, had failed after just 21 hours.

Iran’s Revolutionary Guards have warned that any US warships approaching the Strait to carry out a blockade will be considered a breach of the ceasefire and be dealt with “strongly”, prompting fears that the conflict could reignite just days after a two-week ceasefire was agreed.

Trump wrote on Truth Social: “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.”

He later told Fox News that Nato allies, whom he has criticised for failing to back the war, wanted to help with the operation in the strait. “We have minesweepers there,” Trump said. “And so I understand is the UK and a couple of other countries are sending mine sweepers.”

It was not immediately clear what he was referring to. Earlier, former defence secretary Ben Wallace told The Independent that sending British warships to police the Strait of Hormuz is “a fantasy” because UK armed forces are already so depleted.

In his Truth Social rant, the president said that “any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!”

He added: “Iran will not be allowed to profit off this Illegal Act of EXTORTION. They want money and, more importantly, they want Nuclear. Additionally and, at an appropriate moment, we are fully ‘LOCKED AND LOADED’, and our Military will finish up the little that is left of Iran!”

Addressing Saturday’s failed talks, the US president said the meeting had gone “well” but that no agreement could be found on the “most important issue”, Iran’s nuclear programme.

Iran also said the talks had seen some progress but had failed due to “two important issues”, namely the management of the Strait of Hormuz and Iran’s nuclear programme.

Iran’s Revolutionary Guards responded to Trump’s latest barrage by stating “all traffic… is under the full control of the armed forces”.

In an interview with The New York Times, an Iranian analyst close to the government said the talks had crumbled due to US demands for zero enrichment and the removal of nearly 900 pounds of stockpile uranium, as well as the Hormuz issue. While the talks were ongoing, Iranian state media had accused the US of making “excessive demands”.

A foreign ministry spokesperson said the negotiations took place in an “atmosphere of mistrust”, adding that a deal was always unlikely in the first round of talks – although they confirmed there are currently no plans in place for talks to be resumed.

Sir Keir Starmer, who discussed the negotiations with the Sultan of Oman Sultan Haitham bin Tarik al Said, urged “both sides to find a way through”, a Downing Street spokeswoman said.

But the US president does not appear to be in a hurry to force through a quick peace deal, stating while talks were ongoing that it “makes no difference” to him whether a deal is reached. As the peace talks collapsed, the US president was enjoying a night at the UFC alongside secretary of state Marco Rubio.

Trump faced further criticism regarding his rhetoric when health secretary Wes Streeting accused the president of using “incendiary, provocative, outrageous” language.

“I think we’ve all come to learn that you judge President Trump through what he does, not just what he says,” Streeting added.

He was also critical of the way the US president has focused very personal attacks on the prime minister, such as comparing him to Neville Chamberlain and saying “he is no Winston Churchill”.

Sir Keir and the Sultan of Oman also discussed efforts to reopen the Strait of Hormuz, the closure of which has sent energy prices soaring over the past six weeks.

Despite the differences in Islamabad, three supertankers fully laden with oil passed through the Strait of Hormuz on Saturday, shipping data showed, in what appeared to be the first vessels to exit the Gulf since the ceasefire deal.

But consumer fury has continued to ripple worldwide as high fuel prices filter down to customers. In Ireland, police cleared trucks that had been blocking traffic in central Dublin for five days in a protest against surging fuel prices.

Angered by a more than 20 per cent rise in diesel prices since the outbreak of the war, protesters this week used tractors and trucks to block an oil refinery, two ports, a fuel terminal and a number of roads around the country.