The MOU between the US and Iran, signed on 18 June, was designed to bring about a ceasefire and at least partly reopen the Strait of Hormuz.

The 14-point agreement said Iran would never have a nuclear weapon. It noted that the US, Iran and allies would end military operations on "all fronts" and contained provisions including the end of a US naval blockade and sanctions relief. It also said Iran would "make arrangements using its best efforts for the safe passage of commercial vessels" through the strait and hold talks with Oman over future shipping arrangements.

But it fell apart a short time later when both sides resumed strikes.

Iran has attacked vessels it says have attempted to cross the Strait of Hormuz without authorisation.

The US has attacked Iranian sites in the strait - as well as Iranian tankers off the country's coast. It has also maintained a blockade of Iranian ports, causing huge disruption to the Iranian economy.

Trump since has claimed the US has been successful in getting oil out through the Strait of Hormuz.

However, Yemen's Houthis - allied to Iran - have recently intensified attacks aimed at disrupting oil exports from Saudi Arabia via the Red Sea on the other side of the Arabian peninsula.

During his speech at the UN General Assembly this week Trump said he believed an Iran deal, which has so far eluded him, would come right after November's elections.

"Will a deal be made with Iran that lets them rebuild and create a far greater country than it ever was before?" he said.

"Or do I annihilate the Islamic Republic and do it quickly, never giving them a chance to kill and destroy people and countries again? Do I drive them into hell?"

On Friday, Araghchi said Iran did not accept "coercion, threats or intimidation" and added that "peace cannot be built through threats of annihilation".