Republican presidential candidate Donald Trump asked Florida supporters to pledge that they would vote for him in the primary elections. (Reuters)

ORLANDO -- As Donald Trump rallied thousands of his supporters in the home state of one of his chief rivals, he did something he not done before: He asked those assembled before him to raise their right hand and pledge that they will vote for him in the Florida Republican primary.

"Can I have a pledge? A swearing?" the presidential candidate said, extending his right hand into the air. "Raise your right hand."

Trump then began leading them in a pledge: "I do solemnly swear." The crowd echoed him: "I do solemnly swear."

Trump continued: "That I -- no matter how I feel, no matter what the conditions, if there's hurricanes or whatever." The crowd tried repeating that back, but largely failed in doing so. Trump reassured them that they were doing fine: "That's good enough."

Trump continued the pledge: "Will vote on or before the 12th for Donald J. Trump for president." The crowd repeated the pledge and cheered.

The Florida GOP primary is actually on March 15, but early voting runs until March 12.

Trump has said that he wants to win Florida -- home to rival GOP candidate Sen. Marco Rubio -- and that doing so could end the contentious race for the Republican nomination. Trump spent all of Saturday afternoon in Florida, which he considers his second home after New York, and plans to react to the day's nominating contests at a press conference at his golf course in West Palm Beach.

"If we win Florida, it's over," Trump said. "If we win Florida and Ohio, it's really over."

At the rally, Trump attacked "little Marco Rubio" and pitched himself to the crowd as the only Republican candidate who can beat Democratic front-runner Hillary Clinton, mentioning how she has stopped accusing him of being sexist after he attacked her husband's problems with women.

The rally, held in an arena on the campus of the University of Central Florida, attracted thousands and was interrupted more than a dozen times by protesters. At one point, Trump marveled at how "fun" his rallies are compared to those of other candidates.

Later, two young men got close to the stage and began yelling directly at Trump, as one of them crumpled a campaign sign. Trump stopped speaking and stood on the edge of the stage, watching the two protesters, at least one of whom was black.

As Trump watched, a man in a white campaign T-shirt violently grabbed at least one of the young men and tried taking him down to the ground in a tackle. Security quickly intervened. The crowd chanted: "USA! USA! USA!"

"You know, we have a divided country, folks," Trump said, upon returning to his lectern. "We have a terrible president, who happens to be African American. There has never been a greater division, just about, than what we have right now -- the hatred, the animosity. I will bring people together. I'm going to bring people together, you watch. I'm going to bring people together."