Iran said on Wednesday that it was reviewing a United States peace proposal that sources said would formally end the war, while leaving unresolved the key US demands that Iran suspend its nuclear programme and reopen the Strait of Hormuz.

An Iranian Foreign Ministry spokesperson quoted by Iran’s ISNA news agency said on Wednesday that Tehran would convey its response. US President Donald Trump said he believed Iran wanted an agreement.

“They want to make a deal. We’ve had very good talks over the last 24 hours, and it’s very possible that we’ll make a deal,” Trump told reporters in the Oval Office on Wednesday.

A day before, Trump paused “Project Freedom” to reopen the blockaded strait, citing progress in peace talks. The de facto blockade of the waterway threatens to cause a global recession. Iran has been pressing to keep Hormuz under its control, through which a fifth of global oil and gas supply passes.

Here is more about the US proposal to end the war, and how experts think Iran would respond.

What is the latest US proposal to end the Iran war?

US media outlet Axios said the two sides were “getting close” to an agreement on a 14-point document. Under the memorandum, Iran would agree not to develop a nuclear weapon and halt enrichment of uranium for at least 12 years, it said.

The US would lift sanctions and release billions of dollars in frozen Iranian assets, and both sides, which have imposed competing blockades in the Strait of Hormuz, would reopen the critical waterway within 30 days of signing.

Iran has been under US sanctions for decades, and the lifting of some sanctions under the 2015 nuclear agreement was reversed after Trump walked out of the landmark deal signed under his predecessor, President Barack Obama. Billions of dollars of Iranian assets remain frozen in foreign banks due to the sanctions.

It is unclear how this memorandum differs from a 14-point plan proposed by Iran last week.

The Reuters news agency reported on Thursday, citing a source briefed on the mediation, that the US negotiations were being led by Trump’s envoy Steve Witkoff and son-in-law Jared Kushner. If both sides agreed on the preliminary deal, that would start the clock on 30 days of detailed negotiations to reach a full agreement.

The full agreement would end the competing US and Iranian blockades on the strait, lift US sanctions and release frozen Iranian funds. It would also include certain curbs on Iran’s nuclear programme, which was allowed by the United Nations nuclear watchdog.

While the sources said the memorandum would not initially require concessions from either side, they did not mention several key demands Washington has made in the past, which Iran has rejected, such as curbs on Iran’s missile programme and an end to its support for armed proxy groups in the Middle East.

The sources also made no mention of Iran’s existing stockpile of more than 400kg (900lb) of near-weapons-grade uranium.

Israeli Prime Minister Benjamin Netanyahu, Trump’s ally, said on Wednesday the two leaders agreed that all enriched uranium must be removed from Iran to prevent it from developing a nuclear bomb.

The US and Israel bombed Iranian nuclear sites last June during the 12-day war, after which Trump claimed that Tehran’s nuclear programme was obliterated. A significant portion of Iran’s enriched uranium stockpile remains buried inside the bombed nuclear sites.

Tehran denies wanting to acquire a nuclear weapon. It insists its programme is for civilian purposes as allowed within its position as a signatory to the non-proliferation treaty.

Could Iran agree to this proposal?

Iran has yet to formally respond to the latest US proposal. However, Iranian leaders have pushed back against it.

Iranian lawmaker Ebrahim Rezaee, a spokesperson for the parliament’s powerful foreign policy and national security committee, described the text as “more of an American wish-list than a reality”.

Iran’s Parliament Speaker Mohammad Bagher Ghalibaf appeared to mock reports that the two sides were close, writing on social media in English that “Operation Trust Me Bro failed.”

Al Jazeera’s Resul Serdar Atas, reporting from Tehran, said on Thursday that Iran is still reviewing the US proposal, after which a response is expected to be given to the Pakistani mediators later today.

The Pakistani Ministry of Foreign Affairs said on Thursday that it welcomes the news of a potential agreement between Iran and the US, adding that it will not disclose additional information at this stage.

“As mediators, we will not lose the trust of both parties by revealing details,” it said in a statement quoted by Al Jazeera Arabic.

Atas said, “Iranians are saying that, at this stage, they’re not negotiating their nuclear programme; it’s only about ending the war on all fronts.”

He added that Tehran wants direct guarantees from the UN Security Council, a lifting of sanctions and the reopening of the Strait of Hormuz.

“If that is achieved, in a second phase, they’re ready to discuss their nuclear programme.”

Al Jazeera’s Almigdad Alruhaid reported from Tehran on Tuesday that Iran has set “a very firm red line” on the nuclear file. “The nuclear enrichment programme is non-negotiable,” he said.

According to former US Assistant Secretary of State Mark Kimmitt, Trump’s reported demand that Iran halt all uranium enrichment is unrealistic and unlikely to be accepted by Tehran.

“If there is anything the Iranians are going to insist upon in these negotiations, it is their right to enrich uranium to the 3.67 percent level, which is allowed under nuclear non-proliferation treaties,” he told Al Jazeera.

Kimmitt added that even the 2015 nuclear deal permitted Iran to continue enrichment. Iran boosted its enrichment up to 60 percent after Trump withdrew from the deal in 2018, during his first term.

However, Kimmitt postulated that Trump might want Iran’s existing stockpile of enriched uranium outside of Iran. He added that Iran might either agree to move the enriched uranium outside the country or dilute it down to a non-enriched state.

Alruhaid, the Al Jazeera correspondent, however, said Iran is resisting handing over its existing stockpile of enriched uranium.

Iran is believed to have about 440kg (970lb) of uranium enriched to 60 percent. A 90 percent threshold of enriched uranium is needed to produce a nuclear weapon.

Al Jazeera’s Alruhaid said “the sovereignty on the Strait of Hormuz is becoming one of the main issues on the negotiating table.

“We are seeing the Iranians are tightening their control. They are setting new protocol, new mechanism for controlling that strategic chokepoint for each vessel that is to pass through.”

The US allies in the Gulf, who faced the brunt of Iranian retaliatory strikes, have been pushing for the restoration of navigation in the strait without any conditions. Iran carried out attacks on the Gulf nations, mainly targeting US military assets, after the US and Israel launched attacks on it on February 28.

Trump has repeatedly played up the prospect of an agreement that would end the war, so far without success. The two sides remain at odds over a variety of difficult issues, such as Iran’s nuclear ambitions and its control of the Strait of Hormuz.

A Pakistani source and another source briefed on the mediation told Reuters that an agreement was close on a one-page memorandum that would formally end the conflict, the agency reported on Thursday.

This agreement would kick off discussions to unblock shipping through the strait, lift US sanctions on Iran and set curbs on Iran’s nuclear programme, the sources said.

Al Jazeera, however, could not confirm the veracity of the reports.