WASHINGTON (Reuters) - Former Republican presidential nominee Mitt Romney is expected to say in a video announcement on Friday that he will run for a U.S. Senate seat in Utah, a source familiar with his plans said on Thursday.

Romney, a fierce critic of fellow Republican President Donald Trump, had earlier said he would announce his decision on Thursday but postponed it because of a deadly school shooting in Florida.

The source said Romney, 70, will issue the video announcement on Friday morning. Later on Friday he is scheduled to speak at a Republican Party dinner in Provo, Utah.

Earlier this week, a source familiar with Romney’s plans said he would pledge to “bring Utah values to Washington, D.C.” and planned to run a very Utah-centric campaign.

Romney, a successful businessman, lost the 2012 presidential election to Democratic incumbent Barack Obama. He had served as governor of Massachusetts from 2003 to 2007, after stepping in to lead the organizing committee for the 2002 Salt Lake City Winter Olympics following a bribery scandal.

When Trump’s candidacy gained strength in the 2016 campaign, Romney urged Republicans not to support him, an effort that fizzled as the New York real estate magnate went on to win the nomination and the November election.

Trump had urged incumbent Republican Senator Orrin Hatch to run for re-election in Utah, but Hatch opted not to do so, opening the door to Romney’s candidacy.