Trump says 'last chance' for Iran to strike deal

US President Donald Trump said on Monday that talks with Iran were underway, warning that it was a 'last chance' for Tehran to sign a good deal to end the five-month-old war.

"They are going on right now," Trump told reporters at an Oval Office event when asked about the state of negotiations.

"This is a last chance for them (Iran) to sign a good document," he said.

Trump's comments followed his decision this weekend to call off what he said would be 'massive attacks' he had authorized on Iran, saying talks were to be held, repeating a pattern in which he has vowed major strikes only to cancel them.

In a post on Truth Social later on Monday, Trump called Iran's leadership "unbelievably duplicitous," saying they had asked for a meeting and more talks were scheduled for the "immediate future."

He also repeated his assertion that the US Navy had total control over the Strait of Hormuz, through which a fifth of global oil and liquefied natural gas flowed before the conflict.

"'The United States Wall of Steel!' Nothing gets through to Iran, unless we want it to, and nothing will get through, unless a Deal, or Total Surrender, is accomplished," he wrote.

Monday's developments appeared to fit a pattern that has emerged since Trump launched 'Operation Epic Fury' alongside Israel more than five months ago.

On several occasions, Trump has threatened military action only to later cite diplomatic contacts as a reason for stepping back.

Trump has yet to achieve the objectives he set out at the outset of the war: dismantling Iran's nuclear programme, curbing its ability to attack regional rivals and creating conditions for Iranians to overthrow their clerical rulers.

Repeated US escalations have been met by escalating Iranian responses against US forces in the region, Washington's Gulf Arab allies and shipping, each time ending with Trump stepping back.

The dispute over the Strait of Hormuz remains a central point of contention.

So far the United States has failed to compel Iran to relinquish its grip on the waterway, sending global oil prices higher and pushing up politically sensitive gasoline prices in the United States.

In the latest reported incident in the strait, the British maritime security body UKMTO said overnight that the master of a vessel had reported an explosion in the water near the ship. No one was hurt.