President Trump says US Navy will begin blockade of Strait of Hormuz

Despite his announcement Sunday of a U.S. naval blockade of the Strait of Hormuz, President Donald Trump also urged Iran to open the critical maritime waterway in a subsequent post on his social media platform.

“As they promised, they better begin the process of getting this INTERNATIONAL WATERWAY OPEN AND FAST!” Trump wrote, immediately after the post announcing the blockade.

The president claimed that “Iran promised to open the Strait of Hormuz, and they knowingly failed to do so,” adding that this has caused “anxiety, dislocation, and pain” to the world.

Trump proceeded to rail against the leaders of Iran, despite his previous insistence that there was regime change there and that the new leaders were more “reasonable.”

“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 wrote, adding that they were “very unyielding" during negotiations.

Trump did not go into detail about the negotiations but repeated what Vice President JD Vance said Saturday night about Iran allegedly refusing to give up their nuclear ambitions.

“I could go into great detail, and talk about much that has been gotten but, there is only one thing that matters – IRAN IS UNWILLING TO GIVE UP ITS NUCLEAR AMBITIONS!” the president wrote.

Trump also acknowledged that the "meeting went well" and "most points were agreed to," though he further said that the agreements "don't matter" if Iran is allowed to have nuclear power.

"In many ways, the points that were agreed to are better than us continuing our Military Operations to conclusion, but all of those points don’t matter compared to allowing Nuclear Power to be in the hands of such volatile, difficult, unpredictable people," the president wrote.

-ABC News' Emily Chang

President Donald Trump said that the U.S. will "immediately" begin a blockade of the Strait of Hormuz, following the failure of peace negotiations between the U.S. and Iran.

"[T]he meeting went well, most points were agreed to, but the only point that really mattered, NUCLEAR, was not," Trump wrote on his social media platform Sunday. "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."

The president did not provide specifics in his social media posts. ABC News has reached out to the White House for comment.

Trump's statement comes after Vice President JD Vance, leading a U.S. delegation for high-stakes talks with Iran, said Saturday that the two sides had not reached a deal despite negotiations lasting some 21 hours in Islamabad, Pakistan. Though he declined to provide specifics about why the negotiations deteriorated, Vance said it was in part because the U.S. did not see the "fundamental commitment" from the Iranians not to develop a nuclear weapon in the long term.

Calling Iran's blockage of the Strait of Hormuz "WORLD EXTORTION," the president also said that he had "instructed our Navy to seek and interdict every vessel in International Waters that has paid a toll to Iran. No one who pays an illegal toll will have safe passage on the high seas."

"We will also begin destroying the mines the Iranians laid in the Straits," Trump wrote. "Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!"

"The Blockade will begin shortly. Other Countries will be involved with this Blockade. Iran will not be allowed to profit off this Illegal Act of EXTORTION," the president wrote. "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!"

Mohammad Bagher Ghalibaf, Iran’s lead negotiator, blamed the U.S. for the failure to reach a deal during the talks in Pakistan, citing what he described as a lack of trust.

Ghalibaf, who serves as Iran’s parliament speaker, said on social media that Iran had put forward "forward-looking initiatives," but the U.S. negotiating team failed to win Tehran’s trust during the 21 hours of negotiations.

He added that Washington now understands Tehran's logic and principles, saying that "it’s time for it to decide whether it can earn our trust or not."

-ABC New’s Rashid Haddou

Pakistan said on Sunday it would seek to continue to facilitate "engagement and dialogue" between the United States and Iran.

"We hope that the two sides continue with the positive spirit to achieve durable peace and prosperity for the entire region and beyond," Ishaq Dar, the foreign minister and deputy prime minister, said in a statement.

"It is imperative that the parties continue to uphold their commitment to ceasefire," Dar added.

The minister's statement described the talks held in Islamabad as "intense and constructive," despite their failure reach an agreement.

-ABC News' Rashid Haddou