The White House accused Iran on Wednesday night of acting 'like pirates' after it seized two cargo ships and fired on a third vessel.
Donald Trump had remained quiet over the incidents following his extension of the ceasefire late on Tuesday to allow Tehran more time to submit a unified peace proposal.
However, White House press secretary Karoline Leavitt claimed that the Iranians were 'acting like a bunch of pirates' in taking action against the US blockade of Iran's ports.
Asked whether the US would consider striking the boats, Leavitt says the US 'could' and that the president has 'many options' on the table.
But she added that the seizures were carried out by only two small boats, and Iran's navy is otherwise 'obliterated'.
Iran claimed Wednesday it had seized two cargo ships and fired on a third in the Strait of Hormuz as abandoned peace talks showed no sign of resuming.
Tehran said the MSC Francesca and Epaminondas were 'escorted to the Iranian coast' after Islamic Revolutionary Guard Corps (IRGC) gunboats had opened fire.
The third ship, a Liberia-flagged container vessel, was also fired upon but was not damaged and resumed sailing, according to maritime security sources.
Donald Trump had remained quiet over the incidents following his extension of the ceasefire late on Tuesday to allow Tehran more time to submit a unified peace proposal
Firing line: US Navy image shows the Iranian-flagged cargo ship Touska being intercepted on Monday after it was accused of attempting to violate the US blockade
The IRGC Navy command insisted the cargo ships had 'endangered maritime security' and added: 'Disruption of order and security in the Strait of Hormuz is our red line.'
Secretary-General Arsenio Dominguez, head of the UN's International Maritime Organisation, called for 'innocent seafarers to be released immediately'.
Greece denied that the Epaminondas, which is linked to them, had been seized but confirmed it had been fired upon about 20 nautical miles from Oman.
The vessel's bridge had sustained damage after being hit, but no one was injured in the attack, Greek authorities said.
The move by Iran follows Monday's action when the Iranian-flagged cargo ship Touska was intercepted after it was accused of attempting to violate the US blockade of Iran's ports.
The White House said Wednesday that the President had set no firm deadline for Iran to make a deal. Ms Leavitt claimed 'Operation Economic Fury' was 'completely strangling' Tehran's economy.
She said an 'effective and successful' US blockade had been imposed on Iran's ports and Washington 'will dictate the timeline' of the war.
She also accused Iran of lying about the status of negotiations, claiming: 'What they say publicly is much different from what they concede to the United States and our negotiating team privately.'
Iran has claimed the blockade of its trade by sea is an act of war.
Seized: MSC Francesca was allegedly escorted to the Iranian coast
Attacked: The Greece-linked ship Epaminondas was fired on
Mohammad Bagher Ghalibaf, Iran's chief negotiator, said it is 'not possible to reopen the Strait of Hormuz, considering all the blatant violations of the ceasefire.
They did not achieve their goals through military aggression, nor will they through bullying.'
In a further show of defiance, Iran showcased some of its ballistic weapons in the capital on Tuesday evening in front of a banner depicting a fist choking off the key waterway, through which a fifth of the world's oil passes.
The banners read 'Indefinitely under Iran's Control' and 'Trump cannot do a damn thing'.
Pakistan's mediators continue to try to bring the sides together for negotiations after both failed to show up for planned talks in Islamabad on Tuesday.