The United States attacked and seized an Iranian-flagged cargo ship it said had tried to evade its naval blockade near the Strait of Hormuz on Sunday, and Iran’s joint military command vowed to respond, throwing a fragile ceasefire into question days before it expires.

It was the first interception since the U.S. blockade of Iranian ports began last week. Iran’s joint military command called the armed boarding an act of piracy and a ceasefire violation, the state broadcaster said.

With the U.S.-Iran standoff over the strait sharpening and the ceasefire expiring by Wednesday, it was not clear where President Donald Trump’s earlier announcement on new talks with Iran now stood. He had said U.S. negotiators would head to Pakistan on Monday.

The uncertainty sent oil prices rising again. One of the worst global energy crises in decades threatened to deepen.

Trump on social media said a U.S. Navy guided missile destroyer in the Gulf of Oman warned the Iranian-flagged ship, the Touska, to stop and then “stopped them right in their tracks by blowing a hole in the engineroom.” U.S. Marines had custody of the U.S.-sanctioned vessel and were “seeing what’s on board!”

It was not clear whether anyone was hurt. The U.S. Central Command, which didn’t answer questions, said the destroyer had issued “repeated warnings over a six-hour period.”

Iranian state media suggest new talks won’t take place

There was no comment from Iranian officials directly addressing Trump’s announcement of talks. However, Iranian state media, without citing anyone beyond unnamed sources, issued brief reports suggesting that they would not happen.

Minutes after the ship seizure was announced, Iranian state media reported on President Masoud Pezeshkian’s phone conversation with Pakistan’s prime minister, Shehbaz Sharif, earlier Sunday. U.S. actions, including bullying and unreasonable behavior, have led to increased suspicion that the U.S. will repeat previous patterns and “betray diplomacy,” the reports cited Pezeshkian as saying.

Two previous attempts at talks — last June and earlier this year — were interrupted by Israeli and U.S. attacks.

On another phone call, Iranian Foreign Minister Abbas Araghchi told his Pakistani counterpart, Ishaq Dar, that recent U.S. actions, rhetoric and contradictions were signs of “bad intentions and lack of seriousness in diplomacy,” Iran’s state broadcaster said.

Pakistan did not confirm a second round of talks, but authorities had begun tightening security in Islamabad. A regional official involved in the efforts said mediators were finalizing preparations and U.S. advance security teams were on the ground. The official spoke on condition of anonymity because they weren’t authorized to discuss preparations with the media.

The White House had said Vice President JD Vance, who led the first round of historic face-to-face talks over 21 hours last weekend, would lead the U.S. delegation to Pakistan with envoys Steve Witkoff and Jared Kushner.

Iran on Saturday said it had received new proposals from the United States. While Iran’s chief negotiator, parliament speaker Mohammed Bagher Qalibaf, late Saturday said “there will be no retreat in the field of diplomacy,” he acknowledged a wide gap remained between the sides.

It was unclear whether either side had shifted stances on issues that derailed the last round of negotiations, including Iran’s nuclear enrichment program, its regional proxies and the Strait of Hormuz.

Trump’s announcement on talks repeated his threats against Iranian infrastructure that have drawn widespread criticism and warnings of war crimes. If Iran doesn’t agree to the U.S.-proposed deal, “the United States is going to knock out every single Power Plant, and every single Bridge, in Iran,” he wrote.

Iran wants to control strait

Iran early Monday warned it could keep up the global economic pain as ships remained unable to transit the strait, with hundreds of vessels waiting at each end for clearance.

Security of the strait is not free and “the choice is clear: either a free oil market for all, or the risk of significant costs for everyone,” Mohammad Reza Aref, first vice president of Iran, said in a social media post calling for a lasting end to military and economic pressure on Tehran.

Roughly one-fifth of the world’s oil trade normally passes through the strait, along with critical supplies of fertilizer for the world’s farmers, natural gas and humanitarian supplies for places in dire need like Afghanistan and Sudan.

Iran had announced the strait’s reopening after a 10-day truce between Israel and the Iranian-backed Hezbollah militant group in Lebanon took hold on Friday. But then Trump said the U.S. blockade “will remain in full force” until Tehran reaches a deal with the United States. Iran said it would again enforce restrictions it imposed early in the war. On Saturday, Iran fired at ships trying to transit.