AFP, Washington

Donald Trump is no stranger to provocative language. But his threat to wipe out Iranian civilisation and other recent menacing comments have prompted critics to question the US president’s mental health.

The oldest elected president in American history has ramped up his apocalyptic rhetoric as his frustration grows with Tehran’s refusal to make a deal to end the Middle East war.

Even some former allies have called for the 79-year-old Republican’s removal from office after a series of outlandish and sometimes expletive-riddled social media posts.

The world is now guessing whether Trump will follow through when his Tuesday evening deadline for Iran to reopen the Strait of Hormuz expires -- or back down as the former businessman has often done before.

“A whole civilization will die tonight, never to be brought back again. I don’t want that to happen, but it probably will,” Trump posted on his Truth Social network 12 hours before the deadline falls.

As global alarm grew, the White House was forced to dismiss speculation that his statement -- and comments by Vice President JD Vance about “tools in our toolkit that we so far haven’t decided to use” -- meant Trump was ready to use nuclear weapons.

In the past, the former New York property magnate has often trumpeted a negotiating style that relies on maximalist positions in order to extract more from a deal.

“He does seem a bit more unhinged than in the past,” Peter Loge, director of George Washington University’s School of Media, told AFP. But he added that “this feels to me like a broader pattern of Trump bluster.

“My guess is as we approach one more deadline in a long series of deadlines, the president will declare victory, say I drove Iran to the bargaining table, I’ll give them two more weeks.

“Then we’ll see this movie again in a couple of weeks.”

Even by Trump’s own outspoken standards, he has in recent days used distinctly unpresidential language.

“Open the Fuckin’ Strait, you crazy bastards, or you’ll be living in Hell,” Trump said on Truth Social, on the morning of Easter Sunday.

Trump was barely more measured in a series of interactions with the media in the incongruous setting of an Easter Egg Roll at the White House on Monday.

Surrounded by hundreds of kids and alongside a giant Easter Bunny and First Lady Melania Trump, the president denied that targeting Iranian power plants and civil infrastructure would be a war crime.

His extreme language has prompted a slew of critics -- including some one-time allies -- to question Trump’s sanity.

“We cannot kill an entire civilization. This is evil and madness,” hard-right ex-congresswoman Marjorie Taylor Greene, who split with Trump last year, said on X.

Former loyalists including Greene have also joined Democrats calling for Trump’s cabinet to invoke the 25th amendment, which provides for a transfer of power if a president is unable to govern, particularly in the event of illness.

Right-wing TV host Tucker Carlson called Trump’s Easter Sunday comments the “first step toward nuclear war,” ex-White House press secretary Anthony Scaramucci called him a “crazy person” and sought Trump’s removal from office, and conspiracy theorist Alex Jones asked on his INFO WARS show: “How do we 25th Amendment his ass?”

Former Democratic vice-presidential candidate Tim Walz meanwhile said “the President has lost his mind.”

But Trump himself brushed off questions about his mental health, when asked by an AFP journalist at a briefing at the White House on Monday.

“I haven’t heard that,” Trump said in response to a question about critics saying his mental state should be examined following his “crazy bastards” comment.