Iran has announced an apparent breakthrough in talks with Oman on a new shipping route through the Strait of Hormuz.

After weeks of negotiation, Iran’s Foreign Ministry spokesman Esmaeil Baghaei said the two had finalised the geographical co-ordinates of a navigable channel and were preparing a joint statement.

“Provided that certain third parties do not obstruct the process, a joint statement by the two countries outlining the main considerations and points agreed upon is also being reviewed and finalised,” Baghaei said on Thursday, referring to the US.

However, Reuters reported that the agreement would give Tehran control over ships entering the Gulf in a major concession.

Tehran has insisted it should charge fees for passage in direct conflict with the US and Gulf nations that say it should be free under the UN Convention on the Law of the Sea.

The world is hoping that any proposed agreement could reopen the disputed Strait of Hormuz, a main route for energy supplies from the Middle East.

The latest revelation came as US President Donald Trump claimed the US and Iran had been hunkered down in an “all-day negotiation”.

He also threatened to hit ‌Iran “really hard” if a deal was not reached.

The ‌Strait of ⁠Hormuz “is going to be open very soon,” Trump said.

“If they back out again, they are going to get hit really hard,” Trump said.

However, Iran has previously denied Trump’s assertion that talks have been ‌under way.

Qatar said on Tuesday that mediators were making progress in efforts to end the Iran war.

Iran blocked the Strait of Hormuz after the start ⁠of the war that began on February 28.

The US and Israel attacked Iran and Iran responded with ​its own strikes on ‌Israel and Gulf countries that host U.S. bases.

US-Israeli strikes on Iran ​and Israeli attacks on Lebanon have since killed thousands and displaced millions.

Trump was asked by reporters travelling with him in California about a report on the Axios news site that an announcement on the Strait of Hormuz could be made on Wednesday.

“It could happen. Tomorrow or the next day,” he said, speaking on Tuesday evening California time.

“A lot of progress has been made.”

Oil prices initially eased on hopes of a deal that would allow shipping to resume but later inched upward.

Brent crude, the international standard, was about $US80 per barrel on Wednesday — still well below the levels it hit at the height of the conflict.

The US and Iran reached a deal to open the strait in June, only for attacks to resume.

In recent days, Trump has again alternately threatened massive strikes and voiced support for diplomatic efforts.

Iranian and Omani negotiators have finalised a draft deal to reopen the Strait of Hormuz and are awaiting a final approval from Iran’s supreme leader, two regional officials told the Associated Press on Wednesday.

The officials, who were briefed on the negotiations, portrayed the potential deal as a temporary solution to the US-Iranian dispute over vessels’ transit through the Strait of Hormuz.

They said it is tied to the agreement reached between the US and Iran in June that aimed at ending the fighting and reopening the Strait of Hormuz but which ultimately collapsed.

The officials, who spoke on condition of anonymity to discuss the matter, said the potential deal will pave the way for the US and Iran to resume negotiations to reach a final deal on Iran’s nuclear program.

-with AAP/AP