U.S. President Donald Trump on Sunday appeared to push back his deadline for Iran to reach an agreement on reopening the Strait of Hormuz, posting a vague message simply reading "Tuesday, 8:00 P.M. Eastern Time!”

In a series of interviews and an expletive-laden post on his Truth Social platform on Sunday, Trump doubled down on his threats to devastate Iran's power plants and bridges if Tehran does not end its blockade of the Strait of Hormuz.

The waterway, which is crucial to the global oil and gas trade, has been largely closed since the U.S. and Israel launched large-scale attacks on Iran on Feb. 28.

Trump told the Wall Street Journal that "if they don't do something by Tuesday evening, they won't have any power plants and they won't have any bridges standing."

He appeared to set out 8 pm on Tuesday (0000 GMT Wednesday) as the deadline in a post on Truth Social, after previously signalling an April 6 deadline.

Trump told U.S. media outlet Axios that he sees a "good chance" that Iran reaches an agreement. "But if they don't make a deal, I am blowing everything up over there," he added.

In an earlier post, Trump said: "Tuesday will be Power Plant Day, and Bridge Day, all wrapped up in one, in Iran..."

"Open the Fuckin' Strait, you crazy bastards, or you'll be living in Hell - JUST WATCH!" he continued.

In response, the speaker of the Iranian parliament, Mohammed Bagher Ghalibaf, warned Trump "won't gain anything through war crimes."

"The only real solution is respecting the rights of the Iranian people and ending this dangerous game," he added.

Trump has issued such deadlines before but extended them when mediators have claimed progress toward ending the war, which has killed thousands, shaken global markets and spiked fuel prices in just over five weeks.

"It seems Trump has become a phenomenon that neither Iranians nor Americans are able to fully analyze," Iranian Culture Minister Sayed Reza Salihi-Amiri told visiting Associated Press journalists in an interview in Tehran, adding that the president "constantly shifts between contradictory positions."

The war has engulfed the Middle East and convulsed the global economy.

Iranian missiles have hit Israeli cities and economic infrastructure in the Gulf, sending world energy prices soaring.