United Kingdom Maritime Trade Operations (UKMTO)said on Tuesday that a tanker had reported an external explosion on the vessel's port side, close to the waterline 60 nautical miles off Oman's capital Muscat.

UKMTO said the vessel and its crew were safe, although the tanker reported that some bunker fuel was discharged into the sea.

Iran issued an ominous warning telling the United States to “prepare your bunkers” as renewed US airstrikes cast doubt on hopes of a lasting ceasefire.

Dr Ebrahim Rezaei, spokesperson for Iran’s national security committee, wrote in the aftermath of Monday’s attacks: “To the owners of glass houses; Prepare your shelters. Get your bunkers ready.”

Iranian officials erupted with pointed threats after US forces conducted strikes in southern Iran against military targets in what it described as defensive actions.

US secretary of state Marco Rubio said this morning that the Strait of Hormuz has to be open “one way or the other”, adding that the negotiating language of the deal with Iran could “take a few days”.

Iran’s top negotiator and its foreign minister were in Doha for talks with Qatar’s prime minister on a potential deal with the US to end the three-month-old war, an official briefed on the visit said on Monday, after Washington and Tehran played down hopes of a swift end.

Since a ceasefire took effect last month, Iran and the United States have remained at odds on prickly issues including Iran's nuclear ambitions, Israel's war in Lebanon and Tehran's demands for the lifting of sanctions and the release of frozen assets.

After weeks of mainly indirect talks, both sides say they have made progress on a memorandum of understanding that would halt the war and give negotiators 60 days to reach a final deal.

What are the terms?

The framework is focused on an end to the war and a US naval blockade, in exchange for Tehran taking steps to ensure safe transit in the Strait of Hormuz, according to the Iranian foreign ministry spokesperson, Esmaeil Baghaei.

Senior Iranian diplomat Hossein Nooshabadi told ISNA news agency that the possible framework deal included the end of the war on all fronts including Lebanon, the release of blocked Iranian assets, the lifting of the US naval blockade and the opening of the Strait of Hormuz, the withdrawal of US forces from the region and freedom to sell Iranian oil. He said Iran’s draft contained no commitments on Iran’s nuclear programme.

The Americans insist the nuclear issue must be resolved as part of any deal. A senior US official told Reuters that Iran has agreed “in principle” to reopen the Strait in exchange for the US lifting its naval blockade, and to dispose of Tehran’s highly enriched uranium.

What happens next?

If Iran's Supreme National Security Council approves the memorandum of understanding, it will then be sent to the country's supreme leader for final approval. The US understood Supreme Leader Ayatollah Mojtaba Khamenei had endorsed the broad template of the deal, the senior US official said.

If the first phase of the agreement progressed, the nuclear issue could be reviewed and negotiated during the 60-day period, Baghaei and Nooshabadi said.

The last deal over the nuclear programme - struck in 2015 and torn up by Donald Trump in 2018 - took years of negotiations between large teams of technical experts.

Iran has executed a man for alleged espionage and intelligence cooperation with Israel, the semi-official Tasnim news agency said on Tuesday.

A source said to be close to negotiations tells Iran’s Fars news agency that the unfreezing of Iran’s funds is the last serious sticking point with the United States now being resolved through Qatar mediations.

Donald Trump has warned that Tehran “must understand” it cannot have a nuclear weapon as the two sides edge towards a potential peace deal.

The US says it is close to reaching an agreement with Iran that would end the war and reopen the Strait of Hormuz, with expectations rising that a breakthrough could be imminent.

However, while adopting a more positive tone on Sunday, following previous reports the US was considering further strikes against Iran, Trump said his team would “not be rushed”.

His comments came soon after the US secretary of state Marco Rubio suggested an announcement could be made “within hours”.

Iran is ending a government-imposed internet blackout that has been in place for nearly three months, according to state media.

President Masoud Pezeshkian issued an official order to reopen international internet access, local broadcasters reported on Monday, though independent monitors say the shutdown remains in effect.

The current blackout was introduced in late February following attacks from the US and Israel. It came just weeks after internet restrictions were eased after a similar blackout in January as a result of anti-government protests.

When Donald Trump said that he would probably not be attending his son’s wedding, citing “a thing called Iran and other things”, and when his vice-president suddenly changed his weekend plans to return to Washington, it was not hard to imagine the worst.

That worst, from a great many perspectives, was that the US president had decided to end the ceasefire with Iran and act on his earlier threat to destroy its “whole civilisation”.

So it was an unexpectedly welcome turn of events when Mr Trump revealed on his Truth Social platform that, for the time being at least, almost the opposite was true.

He said that an agreement had been “largely negotiated” with Iran, and added that he had spoken to the leaders of Saudi Arabia and other Gulf countries about a “Memorandum of Understanding pertaining to peace” – peace being spelt out in capital letters.

Israel will escalate strikes against Hezbollah in Lebanon, prime minister Benjamin Netanyahu said on Monday.

Israel and Iran-backed Hezbollah have continued to trade blows despite an April 16 truce aimed at halting the deadliest spillover of the war on Iran.

Tehran has demanded a halt to Israeli attacks in Lebanon as a condition in talks with the US aimed at ending the broader war.

Netanyahu said on Sunday he and President Donald Trump agreed in a phone call that Israel would retain the right to confront perceived threats on all fronts, including Lebanon.

Netanyahu doubled down on that message on Monday night, saying in a video released on Telegram: "We are at war with Hezbollah, and we will intensify our strikes."