Previous Republican presidential competitor Jeb Bush has embraced Texas Senator Ted Cruz for president, calling him a "principled preservationist".

Mr Bush, previous legislative leader of Florida, dropped out of the race a month ago after unfortunate displays in state challenges.

He said Mr Cruz has demonstrated the capacity to engage voters and win essential challenges, as in Utah on Tuesday.

Republicans must "conquer the divisiveness and foulness" Donald Trump has presented, he said.

If not, the gathering will surely lose the White House to Democratic leader Hillary Clinton, Mr Bush wrote in a Facebook post.