Iran's Foreign Minister Abbas Araghchi has accused the US of opting for a "reckless military adventure" every time a "diplomatic solution is on the table".
Iranians would "never bow to pressure", Araghchi said in a post on X, a day after each side accused the other of launching attacks in the Strait of Hormuz and as the US fired on more Iranian vessels.
Despite the clashes, Trump said the ceasefire was intact. It is meant to enable talks to end the war that the US and Israel launched in February.
Iran was expected to respond to US proposals on Friday, according to US Secretary of State Marco Rubio.
"I hope it's a serious offer, I really do," Rubio said during a visit to Italy.
Iran has been controlling the Strait of Hormuz as well as attacking US allies in the Gulf in retaliation for the US and Israeli attacks. Some 20% of the world's oil and liquefied natural gas uses the crucial waterway whose blockage has sent prices soaring.
Early this week, Trump launched - and then paused - a US military operation to help free some 2,000 vessels which have been stranded in the area since February.
The US is also maintaining a naval blockade of Iranian ports in order to exert pressure on Tehran to agree to the US terms - a move that has angered Tehran.
On Friday, US Central Command (Centcom) said US forces had disabled two Iranian-flagged unladen oil tankers attempting to pull into an Iranian port on the Gulf of Oman "in violation of the ongoing US blockade".
US forces had fired "precision munitions into their smokestacks, preventing the non-compliant ships from entering Iran," the statement said.
Centcom said US forces were preventing more than 70 tankers from entering or leaving Iranian ports.
Later on Friday the US signalled its readiness to host a new round of Israel-Lebanon talks next week aimed at halting the clashes in Lebanon between Iranian-backed Hezbollah and Israeli forces.
A spokesperson for the US State Department said the "intensive" talks on 14 and 15 May would aim to deliver "lasting security for Israel, and sovereignty and reconstruction for Lebanon".
The US and Israel say any peace deal requires full disarmament of Hezbollah, but the Shia militant group rejects the talks, which began between the Israeli and Lebanese ambassadors in Washington last month. A fragile ceasefire was agreed, but has been repeatedly broken by Israel and Hezbollah.
Meanwhile, US Vice-President JD Vance met Qatar's Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani in Washington on Friday to discuss Pakistan's mediation efforts between the US and Iran.
The Qatari PM urged all parties to engage with the negotiations to address the "root causes of the crisis" and achieve "lasting peace", a statement on X from the country's foreign ministry read.
The latest US attacks on Iranian targets followed Thursday's exchanges in the Strait of Hormuz, which both sides blamed on each other.
Centcom accused Iran of launching missiles, drones and small boats against three of its warships, in what it called an "unprovoked attack".
Iran's top military command, meanwhile, alleged the US had targeted an Iranian oil tanker and another vessel approaching the Strait of Hormuz and carried out "aerial attacks" on several coastal areas.
One of the cargo vessels attacked near the waters of Minab had caught fire, according to Mohammad Radmehr, an official in the southern Hormozgan province.
"Ten injured sailors have been transferred to hospital, and local groups and search teams are trying to learn the fate of the other sailors," Radmehr told Iranian state news agency Mehr.
US President Donald Trump posted to Truth Social overnight that the US had destroyed multiple small boats, missiles and drones, adding that "great damage" was "done to the Iranian attackers".
"Just like we knocked them out again today, we'll knock them out a lot harder, and a lot more violently, in the future, if they don't get their Deal signed, FAST!"
Additional reporting by Ottilie Mitchell
