US President Donald Trump has launched an extraordinary attack on a female news anchor who he claimed had plastic surgery.
He said MSNBC host Mika Brzezinski was "bleeding badly from a face-lift" during a visit to his Florida golf resort Mar-a-Lago.
In a Twitter salvo, Mr Trump also assailed Ms Brzezinski's MSNBC co-presenter Joe Scarborough.
They are both his occasional sparring partners and she this week accused him of developing a "dictatorship".
"I heard poorly rated @Morning_Joe speaks badly of me (don't watch anymore)," Mr Trump tweeted on Thursday morning.
He also accused "low I.Q. Crazy Mika" and "Psycho Joe" of "insisting on joining me" at Mar-a-Lago over three days at New Year's Eve.
"She was bleeding badly from a face-lift. I said no!" he added.
I heard poorly rated @Morning_Joe speaks badly of me (don't watch anymore). Then how come low I.Q. Crazy Mika, along with Psycho Joe, came..— Donald J. Trump (@realDonaldTrump) June 29, 2017
...to Mar-a-Lago 3 nights in a row around New Year's Eve, and insisted on joining me. She was bleeding badly from a face-lift. I said no!— Donald J. Trump (@realDonaldTrump) June 29, 2017
"The president has been attacked mercilessly on personal accounts by members on that programme," deputy press secretary Sarah Huckabee Sanders told a news briefing.
"And I think he's been very clear that when he gets attacked he's going to hit back.
"The American people elected someone who's tough, who's smart and who's a fighter.
"And that's Donald Trump. And I don't think that's a surprise to anybody that he fights fire with fire."
Ms Brzezinksi, 50, hit back earlier by tweeting an advert for a children's cereal, with the caption, "made for small hands", an apparent reference to a taunt often directed at Mr Trump by his critics.
During his presidential campaign, Mr Trump was a frequent guest on MSNBC's Morning Joe programme, which was accused by liberal voices of giving him preferential treatment.
But the relationship turned sour as the presenters sharpened their scrutiny of the candidate.
The pair have stepped up their attacks since Mr Trump's inauguration, deriding him as a "fake president".
In recent weeks, Mr Scarborough has called Mr Trump a "bumbling dope", resembling "a kid who pooped in his pants", while Ms Brzezinksi has mocked members of the administration as "lobotomised".
Mr Trump's latest broadside comes just a month after Mr Scarborough and Ms Brzezinski, who are engaged to one another, told Vanity Fair magazine the president had offered to officiate at their wedding.
She is the daughter of the late Zbigniew Brzezinski, who was an aide to presidents Carter and Johnson, while Mr Scarborough is a former Republican congressman.
Mr Trump's tirade comes weeks after Ivanka Trump complained about nasty attacks on her father.
"There's a level of viciousness I wasn't expecting" in Washington DC, the first daughter told Fox News.
Online critics have noted the president's wife, Melania Trump, expressed a desire during the election to campaign against cyber-bullying.
But her spokeswoman, Stephanie Grisham, said in a statement on Thursday: "As the First Lady has stated publicly in the past, when her husband gets attacked, he will punch back 10 times harder."
The Democratic National Committee described Mr Trump's tweet as "an attack on women everywhere".
Paul Ryan, the highest-ranking congressional Republican, told a weekly news conference: "We are trying to improve the tone and civility of the debate.
"This doesn't help that."
When asked in the past to clarify Mr Trump's social media postings, White House spokesman Sean Spicer has told reporters "the president's tweets speak for themselves" and they should be considered official statements.
This is Mr Trump's second high-profile spat with a female news anchor.
During a US election campaign debate in August 2016, Fox News moderator Megyn Kelly asked him why he had called certain women "fat pigs, slobs and disgusting animals".
Afterwards, Mr Trump said of Ms Kelly "there was blood coming out of her eyes, blood coming out of her wherever".