UPDATED: Former Republican presidential candidate Mitt Romney is going on the attack against Donald Trump, delivering a speech on Thursday blasting the GOP frontrunner as a “phony” and a “fraud.”

Romney’s staff released excerpts of the fiery speech to the media on Thursday, generating a storm of coverage hours before he even delivered the speech at the University of Utah in Salt Lake City.

“Here’s what I know: Donald Trump is a phony, a fraud,” Romney said. “His promises are as worthless as a degree from Trump University. He’s playing members of the American public for suckers: He gets a free ride to the White House, and all we get is a lousy hat.”

Romney voiced his blunt criticism of Trump, laying out the case against the presidential candidate.

“I believe with all my heart and soul that we face another time for choosing, one that will have profound consequences for the Republican Party and more importantly, for the country,” Romney said at the Hinckley Institute of Politics Forum. “His domestic policies would lead to recession. His foreign policies would make America and the world less safe. He has neither the temperament nor the judgment to be president. And his personal qualities would mean that America would cease to be a shining city on a hill.”

The former governor of Massachusetts even attacked the real estate tycoon’s businesses savvy.

“His bankruptcies have crushed small businesses and the men and women who worked for them,” Romney added. “He inherited his business, he didn’t create it. And what ever happened to Trump Airlines? How about Trump University? And then there’s Trump Magazine and Trump Vodka and Trump Steaks, and Trump Mortgage? A business genius he is not.”

“Donald Trump tells us that he is very, very smart. I’m afraid that when it comes to foreign policy he is very, very not smart,” Romney said.

He also questioned Trump’s mental stability.

“Dishonesty is Trump’s hallmark: He claimed that he had spoken clearly and boldly against going into Iraq,” Romney said. “Wrong, he spoke in favor of invading Iraq. He said he saw thousands of Muslims in New Jersey celebrating 9/11. Wrong, he saw no such thing. He imagined it. His is not the temperament of a stable, thoughtful leader.”

Romney’s speech is the biggest example to date of the Republican establishment’s efforts to stop Trump’s momentum in racking up delegates to secure the party’s nomination in July. The divide in the Republican Party over his candidacy has become an unexpected spectacle in campaign 2016 that is fueling intense media coverage of behind-the-scenes efforts by party leaders to mount an anti-Trump campaign, as well as recent reports about Trump trying to extend an olive branch to party elders.

More Republican leaders, including Senator John McCain, are now starting to come forward following Romney’s remarks.

Romney’s warnings are notable because Trump endorsed the former Massachusetts governor during his White House run in 2012.

Trump, not surprisingly, responded to the reports of Romney’s speech via Twitter, asserting that Romney “ran one of the worst races in presidential history.”

At a rally in Maine on Thursday, Trump said that Romney was “begging” for his endorsement in 2012.

“I could’ve said, ‘Mitt, drop to your knees,’ and he would have dropped to his knees,” Trump said. “He was begging. He was begging me.”

Trump will no doubt generate headlines tonight when he faces off with Fox News anchor Megyn Kelly at the Republican candidates’ debate in Detroit. Trump has publicly bashed Kelly as part of his running feud with Fox News.