Presidential contender Donald Trump has come under attack from his rivals at a Republican debate, after a day in which the party’s veteran politicians urged voters to desert him.
The front-runner in the Republican race was on the defensive in Detroit as Marco Rubio and Ted Cruz piled in.
In a testy debate, Mr Trump admitted he changed his stance on issues but said flexibility was a strength.
Senior Republicans say Mr Trump is a liability who would lose the election.
The debate hosted by Fox News began with Mr Trump being asked about an attack earlier in the day by Mitt Romney, the 2012 nominee, who accused the businessman of bullying, greed and misogyny.
Mr Trump dismissed Mr Romney as a “failed candidate”, but he immediately found himself on the defensive from Mr Rubio.
The Florida senator said he was “not going to turn over the conservative movement to someone who thinks the nuclear triad is a rock band from the 1980s”.
Other debate highlights:
• All three of Mr Trump’s rivals said they would back him if he wins the nomination
• Mr Trump was pressed to move his clothing manufacturing back to the US from China and Mexico
• Ohio Governor John Kasich said he was the “grown-up” on the stage who had the best chance against Democrat Hillary Clinton
• Using a big screen with graphics, Fox host Chris Wallace challenged Mr Trump on whether his planned savings added up
• Texas Senator Mr Cruz said Mr Trump was part of a corrupt Washington system, funding Mrs Clinton’s 2008 election campaign
• Mr Trump justified waterboarding of “animals in the Middle East” and the killing of the families of terrorists
• But he dodged demands to allow the New York Times to release tapes of an “off the record” conversation
In one of the most bizarre moments, Mr Trump defended the size of his hands and then quipped about another part of his anatomy.
There were plenty of personal insults from Mr Trump, who labelled the Florida senator “little Rubio” and the senator from Texas as “liar Ted”.
The New York businessman was forced to explain a civil lawsuit involving the collapse of Trump University.
He said he would win the case but Mr Rubio said he was trying to “con people into giving him their vote, just like he conned people into giving him their money”.
Mr Trump was also challenged by the Fox News panel for changing his stance on Syrian refugees, the war in Afghanistan and President George W Bush.
He replied: “I have a very strong core. But I’ve never seen a successful person who wasn’t flexible, who didn’t have a certain degree of flexibility.”
Hours earlier, Mr Romney led growing calls by leading Republicans against a Trump nomination.
Calling him a “phony” and a “fraud”, the former standard-bearer of the party said Mr Trump’s policies – like the deportation of undocumented migrants and banning Muslims from entering the US – would make the world less safe.
Others like Paul Ryan, John McCain and a host of national security committee members have also attacked the New Yorker since he cemented his front-runner status earlier in the week on Super Tuesday.
Mr Trump, a billionaire with no experience of political office, has won 10 of the 15 states that have voted so far, with his promise to “make America great again”.
His supporters value his perceived authenticity and business acumen, and say he is the strong leader the country needs.
When it comes to Trump, Europe is apoplectic. Fascinated, but appalled.
I’m sometimes asked by Americans what Brits make of Trump and the best analogy I can come up with is this:
Imagine if your much-respected but slightly annoying older sibling (the US) came home with a fantastically unsuitable date (Trump).
Part of you is titillated but part of you is appalled, thinking “Oh my God, this could go horribly wrong”.
With the effective departure of Ben Carson this week, the field of Republican candidates – once 17-strong – has now been narrowed to four.
The debate, sponsored by Fox News, was the first time Mr Trump had faced his rivals since winning seven states on Super Tuesday.
It also brought him face to face with presenter Megyn Kelly, whom he dismissed as a “bimbo” after they clashed in the first primary debate.
This time he was all smiles and he complimented her looks when he took her first question.
In the Democratic race, Hillary Clinton has 10 states, five more than rival Bernie Sanders.
The two will take to the debate stage in Flint, Michigan, on Sunday.