Ann Romney looks on as Donald Trump and Republican presidential candidate Mitt Romney shake hands during a news conference held by Trump to endorse Mitt Romney for president at the Trump International Hotel & Tower Las Vegas on Feb. 2, 2012 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

NEW YORK (CBSNewYork) — Donald Trump is going after Mitt Romney once again after the former Republican presidential nominee announced plans to speak on the “state of the 2016 presidential race” Thursday in Utah.

Trump released an attack video on his Facebook targeting Romney, showing the former Massachusetts governor flip-flopping on issues such as immigration, health care, abortion, the TARP bailouts and global warming.

“Failed Presidential Candidate Mitt Romney is having a news conference tomorrow to criticize me. Just another desperate move by the man who should have easily beaten Barrack Obama,” Trump tweeted, spelling the president’s name wrong.

Failed Presidential Candidate Mitt Romney is having a news conference tomorrow to criticize me. (1/2) — Donald J. Trump (@realDonaldTrump) March 2, 2016

Just another desperate move by the man who should have easily beaten Barrack Obama. (2/2) — Donald J. Trump (@realDonaldTrump) March 2, 2016

He later tweeted, “Looks like a two-time failed candidate Mitt Romney is going to be telling Republicans how to get elected. Not a good messenger!”

Looks like two-time failed candidate Mitt Romney is going to be telling Republicans how to get elected. Not a good messenger! — Donald J. Trump (@realDonaldTrump) March 3, 2016

Trump went after the former GOP candidate last month, calling Romney a “fool” after he insinuated a possible “bombshell” in Trump’s tax returns.

Romney’s speech Thursday will take place at the Hinckley Institute of Politics at the University of Utah at 11:30 a.m.

COMPLETE CAMPAIGN 2016 COVERAGE

Romney announced in January 2015 that he would not be running for president for a third time after flirting with the idea.

CBS News political director and “Face the Nation” anchor John Dickerson told “CBS Evening News” Wednesday that stopping Trump from capturing the Republican nomination is “a long shot.”

“I asked someone involved in the anti-Trump effort to rank the Republican panic on a scale of one to 10, and he said 11. But harnessing that panic requires politicians and party regulars to organize themselves quickly, and there’s no leader in this effort,” Dickerson said. “It requires them to take a big risk. Normally they don’t like to be on the wrong side of public opinion. And there’s no guarantee [it will work] – attacks from establishment could very well make Trump stronger.”

However, an outside group is rushing to raise millions of dollars to stop Trump from becoming the Republican nominee.

Former New Hampshire Gov. John Sununu and Meg Whitman, the chief executive officer of Hewlett Packard, are among the Republican leaders now with Our Principles. The super political action committee had limited fundraising success in earlier weeks, drawing almost all of its funding from the billionaire Ricketts family. The group has spent about $1.5 million on paid television and radio media, most of it ahead of Iowa’s primary caucuses.

“Donors feel guilty they didn’t get active earlier,” Sununu tells The Associated Press.

The plan for Republicans who want to stop Trump is to deny him enough delegates to win the nomination outright, he says.

“Frankly, at this point we want anyone but Trump,” Sununu says of who should become the nominee. “The goal is this: Let’s get to the convention in Cleveland and figure it out there.”

Sen. Marco Rubio, R-Fla., has said that Trump will not get to the magic number of 1,237 delegates for the Republican nomination.

Trump has now won 11 Republican presidential contests and is up to 326 delegates.

“We are going to be a much finer party, we’re going to be a unified party, and we are going to be a much bigger party — our party is expanding,” Trump said during a news conference Tuesday night. “I think we’re going to be more inclusive, more unified, and I think we’re going to be a much bigger party in November.”

(TM and © Copyright 2016 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2016 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)