The US seized an Iranian-flagged cargo ship near the Strait of Hormuz on Sunday, President Donald Trump has said, as Iran rejects a second round of talks, with state media citing the ongoing US naval blockade

The US has seized an Iranian-flagged cargo ship near the Strait of Hormuz after "blowing a hole" in the vessel, Donald Trump said.

The US president wrote on Truth Social that the ship, named the Touska, "tried to get past our Naval Blockade" on Sunday and that "it did not go well" for its crew. He said US Marines intercepted and took "full custody" of the vessel in the Gulf of Oman, in what marked the first such interception since the US blockade of Iranian ports began last Monday.

"The Iranian crew refused to listen, so our Navy ship stopped them right in their tracks by blowing a hole in the engine room," Trump said. "The TOUSKA is under US Treasury Sanctions because of their prior history of illegal activity. We have full custody of the ship, and are seeing what's on board!" There was no immediate comment from Iran.

Iran views the US blockade of maritime traffic entering and leaving its ports as a violation of the two-week ceasefire. Earlier on Sunday, Iranian state news agency IRNA reported that Tehran had rejected a second round of peace talks with the US.

Just hours earlier, Trump said US negotiators would head to Islamabad for talks on Monday night and vowed to "knock out" every power plant and bridge in Iran if Tehran does not agree to a deal with the US, renewing his earlier threats to strike civilian infrastructure that experts have warned would amount to a war crime.

Tehran's absence from the negotiations is due to "Washington's excessive demands, unrealistic expectations, constant shifts in stance, repeated contradictions, and the ongoing naval blockade", IRNA said on Sunday.

The news cast doubt on whether the US negotiators would travel to the Pakistani capital for the talks, which had raised hopes of extending the fragile ceasefire due to expire on Wednesday.

While Iran's chief negotiator, parliament speaker Mohammed Bagher Qalibaf, said in an interview aired on state television on Saturday that "there will be no retreat in the field of diplomacy", he acknowledged that a wide gap remained between the two sides. Pakistan did not confirm a second round of talks, but authorities began tightening security in Islamabad on Sunday.

The White House said Vice-President JD Vance, who led the first round of face-to-face talks lasting 21 hours last weekend, would lead the US delegation to Pakistan alongside special envoys Steve Witkoff and Jared Kushner.

Iran said it had received new proposals from the US on Saturday. It is unclear whether either side had shifted stances on issues that derailed the last round of negotiations, including Iran's nuclear enrichment programme, its regional proxies and control over the Strait of Hormuz.