President Donald Trump announced Sunday that the United States Navy would begin blockading the Strait of Hormuz following the collapse of 21-hour peace negotiations between American and Iranian delegations in Islamabad, Pakistan. U.S. Central Command said the blockade would take effect Monday at 10 a.m. ET, with warships ordered to intercept vessels entering or leaving the strategic waterway. Oil prices surged in early trading after the announcement, with U.S. crude rising 8 percent to $104.24 a barrel and Brent crude climbing 7 percent to $102.29.

Vice President JD Vance, who led the U.S. delegation and said he spoke with Trump at least six times during the talks, stated that Iran had refused to commit to abandoning its nuclear weapons program, which he described as the central sticking point. Iranian state media attributed the breakdown to what it called "excessive demands" by the American side. Trump, speaking to reporters at Joint Base Andrews after returning from Air Force One, said he was not pressing for another round of talks and described what he characterized as significant military gains against Iran, saying "their military is gone" and their missile manufacturing capability was "largely defeated."

Iran's Revolutionary Guards warned that any warships approaching the strait to enforce a blockade would be considered a breach of the current ceasefire and would be met with a strong response, insisting the strait remained under Iranian control. Two U.S. destroyers had crossed the strait without incident on Saturday as part of what the U.S. military described as a mine-clearance mission, though Iranian media reported the vessels were threatened upon departure. Trump also threatened to strike Iranian civilian infrastructure, including water treatment facilities, power plants, and bridges, if Tehran did not agree to give up its nuclear program.

Israel expressed support for the blockade, with Prime Minister Benjamin Netanyahu saying in a video address to his cabinet that Israel backed what he called Trump's "firm stance." Netanyahu said Vance called him from his plane returning from Pakistan and provided a detailed briefing on the negotiations, with the vice president emphasizing that full removal of enriched nuclear material and a halt to further enrichment were the core demands. Netanyahu dismissed reports of any disconnect between Washington and Jerusalem as "the complete opposite" of the truth.

The Strait of Hormuz is one of the world's most critical oil shipping chokepoints, and the blockade announcement carries significant implications for global energy markets and U.S. relations with major oil importers. Approximately 100 tankers have transited the strait since the U.S. and Israel began bombing Iran, with many carrying Iranian oil to China and India, paying up to $2 million per passage. Trump also drew a sharp public rebuke from Pope Leo XIV, whom he criticized as "weak on crime" and "terrible for foreign policy" after the pope condemned U.S. threats to strike Iranian civilian infrastructure and called for a negotiated peace.