Republican Mitt Romney said on Friday he would vote for Senator Ted Cruz in Utah's presidential nominating contest, but the party's 2012 election standard-bearer stopped short of an official endorsement as he urged voters to deny the nomination to front-runner Donald Trump.

In a Facebook post, Romney said a vote for Cruz in Utah's caucus on Tuesday was the best way to prevent Trump from locking down the nomination, which would give opponents a chance to select another candidate at the party's July convention.

"The only way we can reach an open convention is for Senator Cruz to be successful in as many of the remaining nominating elections as possible," Romney wrote.