The US said it launched new strikes on southern Iran, targeting Iranian missile sites and boats allegedly attempting to place mines.
The strikes were carried out in “self-defence” and were designed “to protect our troops from threats posed by Iranian forces”, according to a statement from United States Central Command.
Central Command spokesperson Capt Tim Hawkins said the US military “continues to defend our forces while exercising restraint during the ongoing ceasefire” between the two countries.
Iran has yet to respond to the US attack. However, Iranian Foreign Ministry spokesperson Esmail Baqai earlier said that while some progress had been made in talks aimed at ending the conflict, a deal “is not imminent”.
It remains unclear what impact the strikes will have on any potential peace agreement between the US and Iran.
Following the strikes, US Secretary of State Marco Rubio said a deal was still possible and pointed to talks held on Tuesday between Iran’s top negotiator and foreign minister and Mohammed bin Abdulrahman Al Thani.
“We’ll see if we can make progress. I think there is a lot of back-and-forth discussion regarding specific language in the initial document, so it will take a few days,” Rubio told reporters during an official visit to India.
He added that US President Donald Trump had “expressed his desire” to secure an agreement.
“He’s either going to make a good deal or no deal,” Rubio said.
Asked again later about Monday’s strikes, Rubio said: “The straits have to remain open. They are going to stay open one way or another, so they need to remain open. What is happening there is unlawful, illegal, unsustainable for the world and unacceptable.”
Capt Hawkins said the US strikes targeted an area near Bandar Abbas, a southern port city and home to an Iranian naval base located on the Strait of Hormuz, according to The New York Times.
Iranian state media earlier reported that local officials in Bandar Abbas were investigating explosions heard in the area.
Earlier in May, a confrontation between Iranian and US naval destroyers in the Strait of Hormuz — for which each side blamed the other — prompted Trump to insist that a ceasefire remained in place.
At the weekend, Trump suggested the sides were close to reaching an agreement, but later said he had instructed negotiators “not to rush into” a deal, while Rubio indicated that an agreement could possibly be reached on Monday.
However, Baqai responded: “It is correct to say that we have reached a conclusion on a large portion of the issues under discussion. But to say this means the signing of an agreement is imminent — no-one can make such a claim.”
The memorandum of understanding reportedly under discussion includes a 60-day ceasefire extension, the reopening of the Strait of Hormuz and plans for further negotiations over Iran’s nuclear programme.
According to CBS News, US intelligence believes Iran’s Supreme Leader Mojtaba Khamenei — who was reportedly injured in an Israeli strike at the beginning of the conflict that killed his father and predecessor — is in hiding at an undisclosed location. This has reportedly complicated communication with his envoys and slowed negotiations with the US.
According to US media reports, the talks are not expected to produce an immediate final settlement. Contentious issues, including sanctions relief, the release of frozen Iranian funds and US demands for Iran to curb its nuclear ambitions, are likely to be negotiated at a later stage.
At the beginning of the conflict, Iran was believed to possess around 440kg of uranium enriched to 60% purity — only a short technical step away from weapons-grade 90% enrichment, which could theoretically enable the production of a nuclear weapon.
On Monday night, Trump said the enriched uranium would either be “immediately” handed over to the US or, “preferably, in conjunction and co-ordination with the Islamic Republic of Iran, destroyed in place”.
US and Iranian forces have observed a ceasefire since 8 April. Iran has maintained controls on Gulf shipping through the Strait of Hormuz, while the US Navy has sought to blockade Iranian ports.
The US and Israel launched wide-ranging strikes on Iran on 28 February, triggering conflict across the Middle East. Iran responded by attacking Israel and US-allied Gulf states, effectively closing the Strait of Hormuz. The move caused global oil prices to surge.