Trump says he will unify Republican party

US presidential candidate Donald Trump.

Donald Trump offered an olive branch to Republican party leaders who are deeply opposed to his presidential candidacy Tuesday, making the case he can unify and grow the party.

Emerging from a bitter Super Tuesday marathon as the clear winner, Trump tried to defuse an intra-party feud that may be the only serious obstacle on his path to wining the Republican White House nomination.

Republican luminaries are fighting a rear guard action against his candidacy, which has been marked by racist outbursts and bitter insults.

A long party feud that takes the contest all the way to the convention in July has not been ruled out.

"I'm a unifier," Trump said, easing up on his hallmark bombast and offering a more conciliatory tone. "I know people will find this hard to believe."

Trump tried to knock down, one-by-one, the main criticisms about his candidacy that have come from within his own party: that he's too divisive and cannot win the general election.

"I think we'll be more inclusive and more unified. I think we'll be a much bigger party. I think we're going to win in November," Trump said in Florida after securing victories in at least six states on Super Tuesday, a pivotal day in the 2016 race.