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

'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 posted on Truth Social on Sunday.

The President said that Iran was 'unwilling to give up its nuclear ambitions' as Vice President JD Vance returned from peace talks in Pakistan empty handed.

'I have also instructed our Navy to seek and interdict every vessel in International Waters that has paid a toll to Iran,' Trump added. 'No one who ​pays an illegal toll will have safe passage on the high seas.' 

'Any Iranian who fires at us, or at peaceful vessels, will be BLOWN ⁠TO HELL!' Trump said.

The President, speaking separately on Fox News, announced that NATO would 'begrudgingly' support the US in securing the Strait. He called NATO 'shameful,' claiming that 'they weren't there for us, and they won't be there for us.'

Trump said he was 'very disappointed' in the UK, comparing Prime Minister Sir Keir Starmer to infamous Adolf Hitler appeaser Neville Chamberlain. '[Starmer] made a public statement: "We will send equipment after the war is over." That's a Neville Chamberlain type statement,' Trump told Fox.

NATO has been reluctant to enter the powder-keg Strait of Hormuz. Just 21 miles wide at its narrowest point, filled with mines and within striking distance of missiles and drones fired from a labyrinth of Iranian mountains – any move by the US Navy to blockade the waterway would risk heavy losses. 

Trump is under soaring pressure to bring the war to a close as the price of gas hit $4.20 per gallon – up by more than a dollar since the war started. Other countries, especially in Asia, are more reliant on the Strait – through which a fifth of the world's crude flows. 

Asked whether oil and gas prices would come down before midterm elections in November, Trump told Fox: 'I hope so. I mean, I think so. It could be the same or maybe a little bit higher.' 

Fox's Maria Bartiromo also grilled Trump about his threat last week to annihilate Iran's 'entire civilization' if they did not make a peace deal.

The statement sparked widespread backlash, including from Republican lawmakers, who warned that taking civilian life was unacceptable.  

'I'm fine with it because it brought them to the table,' Trump said of his ultimatum.

'For years, I've had to hear them say death to America. We've had regime change. When I say about a civilization, it really has changed.'

Trump in his statement earlier in the morning insisted that Iran no longer had the military capability to sustain its stranglehold over the Strait of Hormuz. 

'They say they put mines in the water, even though all of their Navy, and most of their "mine droppers," have been completely blown up,' Trump said.

'They may have done so, but what ship owner would want to take the chance? There is great dishonor and permanent harm to the reputation of Iran, and what's left of their "Leaders," but we are beyond all of that,' Trump added.

'As they promised, they better begin the process of getting this International Waterway Open and Fast! Every Law in the book is being violated by them,' Trump said.

Trump also said the US is ready to 'finish up' Iran at the 'appropriate moment, stressing that Tehran's nuclear ambitions were at the core of the failure to end the war.

Face-to-face talks ended earlier Sunday after 21 hours, leaving a fragile two-week ceasefire in doubt.

US officials said the negotiations collapsed over what they described as Iran's refusal to commit to abandoning a path to a nuclear weapon, while Iranian officials blamed Washington for the breakdown of the talks without specifying the sticking points.

Both said their positions were clear and put the onus on the other side, underscoring how little the gap had narrowed throughout the talks.

Neither side indicated what will happen after the 14-day ceasefire expires on April 22. Pakistani mediators urged all parties to maintain it. 

'We need to see an affirmative commitment that they will not seek a nuclear weapon, and they will not seek the tools that would enable them to quickly achieve a nuclear weapon,' Vice President JD Vance said after the talks.

Iran's parliament speaker Mohammad-Bagher Ghalibaf, who led Iran in the negotiations, said it was time for the United States 'to decide whether it can gain our trust or not.'

He did not mention the core disputes in a series of social media posts, though Iranian officials earlier said the talks fell apart over two or three key issues, blaming what they called US overreach.

Iran has long denied seeking nuclear weapons but has insisted on its right to a civilian nuclear program.

It has offered 'affirmative commitments' in the past in writing, including in the landmark 2015 nuclear deal.

Experts say its stockpile of enriched uranium, though not weapons-grade, is only a short technical step away.

Since the US and Israel launched the war on February 28, it has killed at least 3,000 people in Iran, 2,020 in Lebanon, 23 in Israel and more than a dozen in Gulf Arab states, and caused lasting damage to infrastructure in half a dozen Middle Eastern countries.

Iran's grip on the Strait of Hormuz has largely cut off the Persian Gulf and its oil and gas exports from the global economy, sending energy prices soaring.