Washington DC - President Donald Trump threatened to commit a genocide in Iran, saying that "a whole civilization will die" on Tuesday if the country does not accept his war demands.

"A whole civilization will die tonight, never to be brought back again. I don't want that to happen, but it probably will," Trump wrote on his Truth Social platform.

The increasingly erratic and violent 79-year-old already said the US military would bomb Iran's bridges, power plants and other civilian infrastructure into the "stone ages."

Trump has announced a deadline of 8 PM ET Tuesday for Iran to end its de-facto closure of the Strait of Hormuz.

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On Monday, he said a temporary cease-fire proposal being circulated was insufficient.

Iran has rejected US pressure, with state media reporting that Tehran is insisting on guarantees for permanent end to the war.

In his Truth Social post, Trump left the door open for a last-hour agreement.

"Now that we have Complete and Total Regime Change, where different, smarter, and less radicalized minds prevail, maybe something revolutionarily wonderful can happen, WHO KNOWS? We will find out tonight," he wrote.

Trump said Monday that US forces would destroy "every bridge in Iran" and cripple "every power plant" in the country – something that would be a blatant war crime.

US and Israeli warplanes have been continuously bombing Iran since February 28 and on Tuesday, even before Trump's threat about ending "civilization," Tehran said that its crucial oil export terminal on Kharg island was under attack.