A deal to end fighting between the US and Iran is "scheduled to get signed" on Sunday, US President Donald Trump has said - but Iran has cast doubt on the timing.

In a post on social media, Trump also said the Strait of Hormuz, a key shipping route for the world's oil and liquefied natural gas, would be "open to all" following the deal.

Earlier Pakistan, a key mediator, said finalisation of the deal was expected within 24 hours and they were "preparing for the electronic signing".

But Iranian Foreign Ministry spokesman Esmaeil Baghaei expressed caution saying "we will have to wait and see about the exact date of the signing of the memorandum of understanding, although it will not be tomorrow".

Pakistani Prime Minister Shehbaz Sharif added there would be technical-level talks next week if the deal is signed this weekend.

On Friday, Iran's Foreign Minister Seyed Abbas Araghchialso said that a deal to end fighting with the US was close.

Pakistan's prime minister also said the Memorandum of Understanding (MOU) between the US and Iran had been agreed and awaited finalising.

The agreement also envisaged an end to the conflict between Israel and Hezbollah in Lebanon, he said.

Araghchi told Iran's state TV that the deal included reopening the Strait of Hormuz and also the lifting of a US blockade of Iranian ports.

However, he said talks on Iran's nuclear programme would begin later.

US officials have confirmed some of the details of the agreement, saying economic benefits for Iran would depend on Tehran meeting its obligations.

Previous reports from the US had suggested Lebanon may not be part of this deal - with Iran reportedly insisting on it.

The war began with US and Israeli strikes across Iran on 28 February, prompting Iran to attack Israel and US-allied states in the Gulf - as well as effectively closing the Strait of Hormuz.