With oil prices once again dipping lower on hopes of agreement, what do we know about the substance of the document?

- Hormuz reopens? -

US sources confirmed to AFP reporting by the news platform Axios that the two sides have agreed a memorandum of understanding to extend the ceasefire and launch negotiations on Iran's nuclear programme.

Under the reported deal Iran, which has blockaded the Strait of Hormuz and is seeking to charge vessels for passage, would reopen the vital conduit for energy shipments.

Iran would remove any and all mines it has laid in the waterway within 30 days and, in return, the US Navy would halt attempts to enforce a blockade on shipping to and from Iranian ports.

In a Truth Social post, Trump said Iran would end its blockade with "no tolls", but Iranian sources cited by the Fars news agency denied that any such clause exists in the draft.

Iranian sources cited by local media said any deal would be complete only when announced by Tehran, while US Vice President JD Vance countered that the final decision to approve it would rest with President Donald Trump.

- Frozen assets -

Iran had earlier said it was preparing a 14-point framework agreement prioritising an end to the war "on all fronts", including Lebanon, where Israel has stepped up its attacks on Iran-backed Hezbollah.

Iranian officials have publicly disclosed only broad outlines of the proposal, with further details emerging through Iranian media reports.

On Monday, senior Iranian negotiators travelled to Qatar for talks that state media described as part of the diplomatic process.

The Tasnim news agency reported that Tehran was seeking the release of around $24 billion in frozen Iranian assets abroad as part of the agreement.

Around $12 billion "should be made available at the start of the announcement of the memorandum", Tasnim said.

Fars also cited Iranian sources as saying Tehran would not move to the next phase of negotiations until at least $12 billion was released, while Trump said in his post that "no money will be exchanged, until further notice".

There is no official figure for Iran's frozen overseas assets, though Iranian media outlets have recently estimated the total at between $100 billion and $123 billion.

- Nuclear programme -

Iranian officials have said details related to Iran's nuclear programme, a major sticking point for Washington, would be deferred to a later stage after agreement on the framework.

Iranian media reported that nuclear enrichment levels and the fate of Iran's highly enriched uranium stockpile would be negotiated in the 60-day period after the memorandum.

But Trump insisted in his post that the two countries would coordinate on removing and destroying Iran's enriched uranium, a claim Fars cited Iranian sources as describing as "fundamentally baseless".

Iran's foreign ministry has also said there are currently "no negotiations" taking place on the nuclear programme.

It is not yet clear what the initial framework memorandum will say on the nuclear issue.

- Guarantees -

One of Tehran's key demands has been guarantees that Washington will honour any agreement -- after the United States withdrew from a landmark 2015 nuclear deal during Trump's first term in office.

Iran's top negotiator has also expressed scepticism about US guarantees, saying Tehran would trust only Washington's concrete actions, not its words.

If the sides reach an agreement, the final text would be put before the United Nations Security Council for approval, the highest level of guarantee recognised in international law.