U.S. Republican presidential front-runner Donald Trump hunted for votes in three states on Monday ahead of a crucial round of nominating contests, and dismissed outbreaks of violence at his campaign events as "a little disruption."

Trump, who made appearances in North Carolina, Florida and Ohio before Tuesday's primaries, said the establishment Republicans who have labored to stop his outsider candidacy needed to recognize his strength and rally to his cause.

"What they have to do is embrace this phenomenon and go with it. Let's go win," Trump said of party leaders at a rally in Hickory, North Carolina, where he was interrupted several times by protesters.