What do we know about the US-Iran peace deal – and what questions remain?

1. The strait of Hormuz

On Sunday evening, Donald Trump appeared unequivocal about the status of the strait of Hormuz, declaring: “I hereby fully authorize the toll free opening of the Strait of Hormuz, and, simultaneously herewith, authorize the immediate removal of the United States Naval blockade. Ships of the World, start your engines. Let the oil flow!”

An hour later, the US president said the opening of the key waterway through which about a fifth of the world’s oil flows was contingent upon the signing of a deal, scheduled for Friday, and would be “for purposes of mine removal”.

Crucially, Pakistan’s prime minister, Shehbaz Sharif, the peace deal mediator, made no mention of the strait in his opening announcement. Iran’s Mehr state news reported that the agreed memorandum of understanding calls for the reopening of the strait within 30 days under “Iranian arrangements”.

The US has long been adamant that any tolling arrangements on shipping – such as those reportedly discussed with Oman – would be unacceptable. The US president said last month: “The strait is going to be open to everybody. Nobody’s going to control it.”

The leaders of the UK, France, Germany and Italy – a grouping called the E4 – were also quick to emphasise that the reopening of the strait must be unconditional and with unrestricted freedom of navigation.

Regardless of the uncertainty, global oil prices tumbled in the hours following the news, with prices falling to their lowest levels since early March, shortly after the Iran war began. Prices plunged despite warnings that it could take months or years to restore the Gulf’s energy production. Reopening oil and gas sites is a complex process, and some of the region’s infrastructure has been damaged by drone attacks. There is also the question of whether shipping companies and insurers will feel the strait is safe enough for passage.

2. Lebanon

A key point of disagreement during early ceasefire talks was whether Lebanon would be included in any deal.

Iranian deputy foreign minister Kazem Gharibabadi was unequivocal about the scope of Sunday’s agreement, saying: “A permanent and immediate end to the war has been declared on all fronts, including Lebanon.”

Mediator Sharif was clear, too, saying in a social media post: “Both sides have declared the immediate and permanent termination of military operations on all fronts, including in Lebanon.”

But Trump made no mention of Lebanon in his initial announcements on Truth Social, focusing almost exclusively on the strait of Hormuz.

This could be difficult to accept for Israel, which has not been included in the Iran peace negotiations and did not immediately respond to news of the deal. Its prime minister, Benjamin Netanyahu, arguably has his own domestic political reasons to continue pursuing the conflict with Iran and its proxies, including Hezbollah in Lebanon. Further military action could conceivably torpedo any agreement between the US and Iran.

Earlier plans to unveil a deal with Iran on Sunday were upset by an Israeli attack on Beirut, which destroyed a building in the Lebanese capital’s southern suburbs, killing three and injuring six. Trump told the Axios news site that the strike had “delayed the signing by a few hours”.

Trump and Netanyahu have repeatedly clashed over Israel’s military operations in Lebanon, which continued as part of a separate and frequently ignored ceasefire deal. Two weeks ago, Trump reportedly called him “fucking crazy” after a launching a strike on Beirut, adding: “You’d be in prison if it weren’t for me.” After the latest strike the weekend, he said Netanyahu had “no fucking judgment”.

3. Iran's nuclear program

By any assessment, the fate of the Iran’s nuclear program – a key rationale given by Trump for the war on Iran – has not been resolved in the latest agreement.

The president repeated on Sunday his promise that “Iran will never have a nuclear weapon” but senior Pakistani officials told the Associated Press that nuclear talks would continue over the next 60 days. Trump himself told the New York Times that if Tehran failed to reach a nuclear deal, it could come under fresh attack by the US military.

In a joint statement with the E4 grouping of the UK, France, Germany and Italy, echoed Trump’s comments on Sunday night, adding: “We are prepared to lift relevant sanctions in response to clear, verifiable steps by Iran on its nuclear program.”

Iran has long maintained its nuclear program is peaceful and has not publicly committed to giving up the enriched uranium, which is believed to be buried under three nuclear sites that were badly damaged by US strikes last year.

Trump faces significant political pressure to secure a better deal on this issue than the one he scuppered during his first term. He withdrew the US from a 2015 multilateral Iran deal, negotiated by Barack Obama, that lifted sanctions on Tehran in exchange for limits on its nuclear program, including international inspections.

Iran responded by ramping up its enrichment of uranium, producing more than 400kg of material at close to bomb-grade purity. The eventual fate of that uranium is likely to be a key negotiating point during ⁠the upcoming broader talks.

Republican senator Lindsey Graham said on Sunday he would be “watching closely” the coming nuclear negotiations.