Donald Trump
Donald Trump Reuters

Ahead of his speech at the University of Utah on Thursday, former Republican presidential nominee Mitt Romney verbally lashed out at Republican candidate Donald Trump, in a plea for fellow Republicans to shun the business mogul.

The former Massachusetts governor branded Trump as “a phony, a fraud” whose “promises are as worthless as a degree from Trump University.” Romney Further accused the GOP frontrunner of threatening America’s future and “playing the American public for suckers.”

In his prepared remarks, Romney said that Trump “has neither the temperament nor the judgement to be president.” Previously, Romney has only criticized Trump through social media and press interviews, but now following Super Tuesday in which Trump made a strong showing, he has increased his effort to prevent Trump from winning the nomination.

“Only (Ted) Cruz, (Marco) Rubio and (John) Kasich have serious policy proposals to address the broad range of national challenges,” said Romney endorsing Trump's rivals.

Romney further said that a Trump nomination at the party’s convention in Cleveland in July would allow Democrat Hillary Clinton to win the presidency.

“A person so untrustworthy and dishonest as Hilary Clinton must not become president. But a Trump nomination enables her victory,” said Romney, accusing Clinton of compromising national secrets with her use of an illegal private email server during her stint as secretary of state.

Mr. Trump has already fired back in a series of Twitter posts calling Romney a “failed candidate,” referencing his defeat by President Barack Obama in his 2012 re-election. “Why did Mitt Romney beg me for my endorsement four years ago?” wrote Trump, who indeed endorsed Romney in the 2012 race.

Trump has 316 delegates so far, Cruz has 226, and Rubio has 106. It takes 1,237 delegates to win the party nomination.