With less than 48 hours before a US-Iran ceasefire was set to expire, the Pentagon confirmed on April 19 that US forces had opened fire on an Iranian cargo vessel attempting to breach an American blockade line — and seized the ship.
Tehran called it "armed piracy." The incident cast a long shadow over a second round of peace negotiations scheduled in Pakistan, while once again sending global energy markets into turmoil.
According to The New York Times and the Associated Press, President Donald Trump personally announced the military action on his Truth Social platform. He said the guided-missile destroyer USS Spruance had fired on an Iranian-flagged cargo vessel named the Touska in the Gulf of Oman, claiming American forces had "blown a big hole in their engine room, stopping them dead in their tracks."
Trump added that the Touska had been sanctioned by the United States due to a "record of prior illegal activity," and that US Marines now had full custody of the vessel and were inspecting its cargo.
The Associated Press noted it remained unclear whether the incident had resulted in any casualties. US Central Command, in a statement to the media, said only that the destroyer had "issued multiple repeated warnings over a six-hour period" before opening fire.
The New York Times, citing Iran's semi-official Mehr News Agency, reported that Tehran acknowledged the firing but claimed IRGC naval forces had intervened and "forced the Americans to retreat." Iran's Joint Military Command condemned the boarding attempt as armed piracy and accused Washington of openly violating the ceasefire.
An Iranian military spokesperson warned that "Iran will soon respond and retaliate against the armed piracy of the US military." He noted the cargo ship had recently departed from Malaysia after a prior stop in China.
Editor's note: Iran's state media described the vessel as having come from China. Vessel-tracking firm TankerTrackers confirmed the ship departed from Port Klang, Malaysia, with a prior port call in China en route to Iran.
Diplomatic mediation in disarray
The timing could hardly have been worse. The two sides had been expected to convene a second round of negotiations in Islamabad, Pakistan on April 20 — and whether those talks would go ahead remained deeply uncertain.
Pakistan, serving as mediator, was still making security preparations for negotiations that appeared increasingly at risk of collapse. The New York Times reported that Islamabad entered a security lockdown Sunday evening, with officials disclosing that up to ten thousand additional security personnel would be deployed across the city.
Reuters, citing two Pakistani security sources, reported that two American C-17 military transport aircraft landed at a local air force base on the afternoon of April 19, delivering security equipment and vehicles ahead of the US delegation's arrival.
The Associated Press reported that municipal authorities had suspended public transportation and barred heavy vehicles from the city center. Barbed wire barriers went up near the Serena Hotel — venue of the first round of talks the previous week — and guests were asked to check out. A regional official confirmed to the AP that an American advance security team had already arrived on the ground.
Despite Pakistan's extensive preparations, the signals from both sides were deeply contradictory.
White House officials initially said the US delegation would be led by Vice President JD Vance, alongside special envoy Steve Witkoff and Trump son-in-law Jared Kushner. Trump had posted on April 18 that the American team had already departed for Pakistan. But he later clarified that Vance would not make the trip, citing last-minute security constraints — leaving Witkoff and Kushner to lead the delegation.
Trump characterized the American proposal as a "very fair and reasonable" deal, while threatening to destroy every power plant and bridge in Iran should Tehran refuse.
Tehran responded with open hostility. Iran warned that any US strike on civilian infrastructure would trigger retaliation against the power plants and desalination facilities of neighboring Arab states.
The Associated Press, citing Iranian state media, reported that Tehran had declared it would not attend a new round of talks. Reuters, citing IRNA, said Iran formally rejected further negotiations over Washington's continued blockade, threatening statements, shifting positions, and excessive demands.
Iranian state media then published accounts of a phone call between President Masoud Pezeshkian and Pakistani Prime Minister Shehbaz Sharif, in which Pezeshkian accused US conduct of deepening suspicions that Washington would again "betray diplomacy."
Foreign Minister Abbas Araghchi, in a separate call with Pakistani Foreign Minister Ishaq Dar, said recent American actions were "signs of a lack of sincerity and a failure to take diplomacy seriously." Deputy Foreign Minister Saeed Khatibzadeh was more blunt: Tehran saw no point in face-to-face talks so long as the Americans had "not abandoned their maximum pressure stance."
The Strait of Hormuz remains closed
Iran's chief negotiator, parliament speaker Mohammad Baqer Qalibaf, acknowledged in a nationally televised interview on April 18 that while some progress had been made, significant gaps remained on nuclear enrichment, regional proxy forces, and control of the Strait of Hormuz.
He was emphatic that Iran would make "no concessions" at the negotiating table.
Although the ceasefire agreement was predicated on the reopening of the Strait, both sides appeared to be maintaining blockade operations, with large numbers of tankers forced to anchor outside the waterway.
Trump separately accused Iran of attacking two ships attempting to transit the Strait on April 18, calling it "a complete violation of our ceasefire agreement." Reuters, citing Iranian sources, reported that armed forces had turned away two liquefied petroleum gas tankers that day. Vessel-tracking data from MarineTraffic showed that one of them — the Angola-flagged LPG carrier G Summer — managed to exit the Persian Gulf only on a second attempt.
Iranian First Vice President Mohammadreza Aref put Iran's position starkly: "One cannot restrict Iran's oil exports while expecting others to enjoy free security guarantees. The choice is clear: either a free oil market for all, or everyone sharing the risk of enormous costs."
Iran's Supreme National Security Council went further, declaring on the evening of April 18 that "Iran is determined to maintain oversight and control of traffic through the Strait until the war has completely ended."
The markets are watching. Reuters noted that this conflict — now entering its eighth week — has inflicted the most severe disruption to global energy supplies in modern history. Brent crude futures surged on April 20, reaching a high of approximately $96–97 per barrel, while S&P 500 index futures fell roughly 0.9%.
Trump had previously described elevated oil prices as "temporary." But US Energy Secretary Chris Wright acknowledged on April 19 that while American gasoline prices may have peaked, they could remain elevated for several months.
The human toll continues to mount. The conflict, which erupted on February 28, has claimed the lives of more than 3,600 people inside Iran, more than 2,167 in Lebanon, at least 40 in Israel, and more than ten in Arab Gulf states. At least 13 American military personnel have also died.
Reuters reported that European Union member states are growing concerned that Washington's negotiating team — in pursuit of short-term political gains — is pushing for a hasty agreement that could require far more extensive remediation in the future.
