Washington: Donald Trump came under intense scrutiny Friday after he disparaged former Miss Universe Alicia Machado in a series of scathing early morning statements on Twitter, including an accusation that she had appeared in a sex tape.

His rival, Hillary Clinton, swiftly seized upon the attacks to characterise Trump as “unhinged.”

The Republican presidential nominee called Machado “disgusting” and a “con” and raised questions about her past in a series of tweets fired off between 3am and 5:30am, his most negative comments after days of attacks on her.

The former Miss Universe’s story has dominated media coverage of the election since Clinton brought her up at Monday’s debate, where she criticised Trump for denigrating comments he made in 1996 about Machado’s weight.

The fallout has threatened to undermine weeks of carefully choreographed efforts by Trump’s campaign to repair his image after several missteps this summer, most notably his feud with the family of a Muslim American soldier who died in Afghanistan.

“For the last month, he’d managed to stay on script and read off the teleprompter. We’d almost forgotten what an erratic, wild and mean man he can be. The Machado thing set him off like a keg of dynamite,” said Republican strategist Ana Navarro, who has been very critical of Trump. “It is a shocking smallness and pettiness on his part. It is the Khans and Judge Curiel all over again. He and his wild pack of surrogates have been viciously attacking this woman for five days now,” she said, referring to the soldier’s family and the judge whose impartiality Trump questioned because of his Hispanic heritage.

“Forget being president. This guy isn’t fit to take care of a puppy,” Navarro added.

Clinton’s campaign responded forcefully, accusing Trump of misogyny and questioning his temperament.

Speaking to a late afternoon rally in Coral Springs, Florida, she mocked Trump’s early morning tweet storm and called it a “meltdown.”

“Who gets up at 3 o’clock in the morning to engage in a Twitter attack against a former Miss Universe?” she asked. “Really, why does he do things like that?”

Clinton said Trump’s behaviour was “unhinged, even for him” and was further evidence that he is “temperamentally unfit to be president of the United States.”

“A man who can be provoked by a tweet should not be anywhere near the nuclear codes,” she said.

On Friday afternoon, BuzzFeed News uncovered an explicit Playboy video from 2000 in which Trump made a cameo. The film, titled “Playboy: Video Centrefold,” featured nude women in sexual positions. Trump made a brief appearance in the film, according to BuzzFeed, and did not appear in pornographic scenes.

Clinton’s campaign on Friday evening mocked Trump over his appearance in the film.

“There’s been a lot of talk about sex tapes today, and in a strange turn of events, only one adult film has emerged today, and its star is Donald Trump,” Clinton spokesman Nick Merrill told a group of reporters stationed outside a fund-raiser in Miami Beach.

Trump offered no evidence to support his allegation that Machado had a sex tape, a rumour that had widely circulated on the internet. The GOP nominee appears to have been referring to racy but not explicit footage from a Spanish-language reality television show called “La Granja,” on which she appeared in 2005.

In an attempt to discredit Machado, Trump’s allies have also pointed to news reports of an incident in 1998 in Venezuela, in which Machado was suspected of having driven a getaway car for her then-boyfriend after he shot someone. She allegedly later threatened the judge in the case.

No charges were filed against her, and earlier this week, she called those reports “speculation.”

Trump has also alleged that Clinton helped Machado become a US citizen to attack him. There is no evidence supporting that claim, either.

In a statement in Spanish released on her Instagram account Friday, Machado blasted Trump for attacking her “with the goal of intimidating me” through “slurs and false accusations” that she said were circulated by sensationalist journalists. She accused him of decades of misogyny and vowed to continue supporting Clinton’s candidacy.

“When I was just a young woman, the now-candidate humiliated me, insulted me, publicly disrespected me, as he did often in private in the cruelest way. Just like this happened to me, it’s clear over years that his actions and conduct have been repeated with other women for decades,” she wrote in Spanish.

Pastor Robert Jeffress, a vocal Trump supporter and a Dallas-based evangelical leader, defended Trump and said conservative religious voters are unlikely to mind.

“I do not take literally that he has asked people to sit down and watch a sex tape,” Jeffress said. “I don’t think Donald Trump wants people to watch a sex tape. He’s simply saying people should consider her past when they look at the situation.”

Rep. Steve King, R-Iowa, a conservative leader who has endorsed Trump, suggested that Trump should “let some others bring up the points he made in his tweets. Plenty of high-profile voices could have brought his points out.”

“Maybe he got fed up and said, ‘Let’s blow this issue up and put it behind us.’ I get it,” King said. “And I know he has so many Twitter followers, so he thinks he’s the one to make his view penetrate, to get the truth out there in the media. But he can have others do this kind of thing for him.”

When asked about the timing of Trump’s tweets, King said, “Are you sure he got up from bed? He may have never been to bed. I bet he’s not getting too much sleep these days being in the middle of a campaign.”