Former Republican nominee Mitt Romney called Donald Trump a ‘misogynistic, reckless fraud’ who could destroy America during a speech in Utah on Thursday.
Trump blasted his one-time supporter, whom he said once “begged” for his endorsement.
“I could have said, ‘Mitt drop to your knees,’ and he would have dropped to his knees,” Trump said. “Mitt is a failed candidate – he failed. He failed horribly.”
The BBC reports
He accused Mr Trump of bullying, misogyny and dishonesty in a speech in Utah on Thursday.
“Prospects for a safe and prosperous future are greatly diminished” if Mr Trump becomes the nominee, he added.
Mr Trump has meanwhile mocked Mr Romney on Twitter as a “failed candidate” who should not advise on electability.
Many senior Republicans are alarmed at the prospect of Mr Trump securing the nomination for November’s election.
In the latest attack from top figures in the party, several members of the Republican national security community wrote an open letter describing Mr Trump’s “vision of American influence and power in the world” as “wildly inconsistent and unmoored in principle”.
“He swings from isolationism to military adventurism within the space of one sentence,” the letter said.
John McCain The 2008 presidential nominee has also joined the verbal attack on the Republican front-runner, describing Mr Trump’s statements on national security as “uninformed and dangerous”.