WASHINGTON/TEHRAN/LONDON - Tehran has called its decision not to take part in the second round of peace talks with the United States in Pakistan as "definitive", Iran's semi-official Tasnim news agency said Tuesday.

The decision was announced shortly before US President Donald Trump said he would extend the ceasefire to allow more time for negotiations, as the current two-week truce is set to expire on Wednesday night.

Tasnim said the Pakistani mediator has been informed of Iran's decision, which has been made aiming to completely protect the Iranian people's rights.

The report noted that, despite propaganda and rumors spread by US media and officials, the Iranian negotiating team will not travel to Pakistan for talks on Wednesday for various reasons already relayed to the United States through Pakistan.

Tasnim said the United States has continued its naval blockade against Iran and made what it described as "excessive demands" in recent exchanges between the two sides, which it said prevented significant progress. It added that US naval pressure, including the blockade and other "hostile actions", along with what it described as breaches of commitments, hindered Iran's participation in the next round of talks in Islamabad.

Trump said the United States had agreed to delay a planned strike on Iran to give Tehran time to come up with a "unified proposal" ahead of possible negotiations.

ALSO READ: Iran-US ceasefire nears expiry as Hormuz tensions cloud talks

Meanwhile, Mahdi Mohammadi, the Iranian parliament speaker's advisor on strategic affairs, said after Trump's Truth Social post on Tuesday that the ceasefire extension announced by Trump is a "ploy" to buy time for a surprise attack, warning that continued US pressure at sea would require a response.

Delegations from Iran and the United States had been expected to hold the second round of their peace talks in Pakistan this week. The two countries held their first round of talks on April 11-12 in Islamabad, and the negotiation failed. 

Trump also said late Tuesday that any move by the United States to reopen the Strait of Hormuz would preclude a deal with Iran, warning that an agreement would be impossible unless "we blow up the rest of their country."

He said in a Truth Social post that the Iranian leaders are also "included" in the potential move to bomb Iran.

Trump said on Monday that it was "highly unlikely" for him to extend the truce, and on Tuesday morning, he told US media that he doesn't want to do that, expecting the US to "end up with a great deal" with Iran while threatening to bomb Iran again if no deal is reached.

US Vice President JD Vance, whose trip to Pakistan for talks with Iran has been put on hold, was at the White House for meetings on Tuesday, along with Trump's envoy Steve Witkoff and son-in-law Jared Kushner, multiple media outlets reported.

US Secretary of State Marco Rubio and Secretary of Defense Pete Hegseth arrived at the White House on Tuesday afternoon to join discussions over Washington's next steps, according to the reports.

The US violated the ceasefire by starting a naval blockade of Iran's ports, Iranian Foreign Minister Abbas Araghchi said Tuesday on X.

Iran's Foreign Ministry spokesman Esmail Baghaei told state TV late Tuesday that Iran has not yet decided whether to join fresh peace talks since it was upset about what he called mixed messages from Washington.

"It is not out of indecisiveness, it is because we are facing contradictory messages and behaviors, and unacceptable actions from the American counterpart," Beghaei said.

As US forces have intercepted and taken custody of an Iranian-flagged cargo ship on Sunday and Iran has not yet announced its decision to send a negotiating team for talks, the prospect of an expected second round of US-Iran talks remains unclear, according to media reports.

Iranian gunboat fire on container ship

Also, on Wednesday, a container ship was fired upon by an Iranian gunboat off the coast of Oman, damaging the vessel's bridge, the United Kingdom Maritime Trade Operations (UKMTO) said in a report.

The ship's master reported that a gunboat believed to be linked to Iran's Islamic Revolutionary Guard Corps approached and opened fire without issuing a distress signal or very high frequency challenge, the UKMTO said, leading to a surprise attack.

All crew members are safe, and the attack resulted in substantial damage to the ship's bridge, the report added. No fire or environmental damage has been reported.

"The situation continues to be volatile. Ships should take maximum caution and not take risks without security guarantees," a spokesperson for the International Maritime Organization said in a statement on Monday.