US President Donald Trump has rejected an Iranian proposal to reopen the Strait of Hormuz to commercial shipping within a week.

He told reporters at the White House that Tehran "want to make a deal where they open the Strait immediately because they're losing so badly".

On Friday, Iran's Foreign Minister Abbas Araghchi told reporters at the UN in New York that agreement could be reached "if the necessary conditions are met" and that these were contained in a memorandum of understanding (MOU) signed by the two countries in June.

The vital waterway through which around a fifth of the world's gas and oil supply usually flows has been effectively closed since the outbreak of war in February.

"I'm rejecting their deal," Trump said on Saturday, adding that the US already had "total control" of the strait, with "massive amounts of oil" passing through it.

"They want to make a deal, and I think that's fine. I like making a deal, too. But that deal would not be acceptable," he added.

On Friday the Wall Street Journal, external cited officials as saying Trump was sceptical that Iran would meet his demands and had told his staff that he saw a renewed bombing campaign as probable.

Iran responded to US and Israeli air strikes, beginning in late February, by attacking Israel and US bases in the Gulf and Arab Gulf allies of the US - as well as blocking the Strait of Hormuz. Its closure has caused wild fluctuations of energy prices.

The economic effects have also increased pressure on Trump to find a way of ending the conflict - particularly as the US heads towards Congressional elections in November.

The MOU signed in 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 their allies would end military operations on "all fronts" and contained provisions including ending a US naval blockade and other sanctions.

It also said Iran would "make arrangements using its best efforts for the safe passage of commercial vessels" through the strait.

But the deal fell apart after both sides resumed strikes. Iran has attacked vessels it says have attempted to cross the strait 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 has since claimed the US has been successful in getting oil out through the Strait of Hormuz.

Shipping data shows a recent 10-day average of about 18 transits per day, with numbers dropping as low as nine vessels on certain days, according to Kpler, a commodities analytics firm cited by Reuters.

The situation has been exacerbated by Houthi attacks on Saudi oil installations.

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

The group seized strategic stretches of Yemen's Red Sea coast this month, including the port of Mokha, which overlooks the Bab al-Mandab Strait, another chokepoint for global shipping.