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Kiichiro Sato, Associated Press
Lindsay Otters of Waverly, Ohio, waits in line with her 3-month-old daughter Emma outside of the Wright Brothers Aero Hangar for a rally by Republican presidential candidate Donald Trump Saturday, March 12, 2016, in Vandalia, Ohio.

PALM BEACH, Fla. — Republican presidential candidates Marco Rubio and John Kasich suggested Saturday they may not support Donald Trump if he becomes the GOP nominee, as violence at the front-runner's rallies deepened the party's chaotic chasm.

Rubio told supporters that while he was currently sticking with his pledge to back the nominee if he wasn't the party's choice, "it's getting harder every day."

Kasich said the "toxic environment" Trump is creating "makes it extremely difficult" to support him.

Rubio and Kasich have previously committed to backing Trump should he win the Republican nomination, despite reservations about his qualifications. Their shift came hours after clashes between Trump supporters and protesters Friday night in Chicago.

"To see Americans slugging themselves at a political rally deeply disturbed me," Ohio Gov. Kasich, said while campaigning in Cincinnati. "We're better than that."

Rubio, speaking in Largo, Florida, said: "Last night in Chicago we saw images that made America look like a third world country." Trying for a win Tuesday in home-state Florida to keep his GOP campaign alive, Rubio said that while some of the blame of lies with the protesters, much of the divisiveness is in Trump's hands.

"This is what a culture and a society does when everyone does whatever they want," he said. "This is what happens when political candidates talk like people on Twitter."

In Dayton, hundreds of people staked out spots for Trump's rally at a hangar, and long lines passed passing through security screenings.

Claudia Young and her husband, Michael, came from Muncie, Indiana, arriving more than three hours before the late-morning event.

Her view on what happened in Chicago? "We're supposed to have freedom of speech in this country, but the people who came to see Trump couldn't listen to what they wanted to hear."

There were about a dozen young protesters on a corner about half a mile away from the hangar. Messages on their signs included "Make love, not walls," and "Jews and Muslims United."

On Friday night in Chicago, raucous cheers broke out among a large portion of the crowd — and the spark was Trump's decision to cancel.

Some isolated confrontations took place afterward. Police reported arresting five people. Many anti-Trump attendees had rushed onto the floor of the University of Illinois at Chicago Pavilion, jumping up and down with their arms up in the air.

"Trump represents everything America is not and everything Chicago is not," said Kamran Siddiqui, 20, a student at the school who was among those celebrating. "We came in here and we wanted to shut this down. Because this is a great city and we don't want to let that person in here."

Some supporters of the Republican front-runner started chanting "We want Trump! We want Trump!" in response to the celebrations.

"It's a shame," said Trump supporter Bill Tail, 43, of the Chicago suburb of Oaklawn. "They scream about tolerance, but are being intolerant themselves. That doesn't make sense."

As Trump attempts to unify a fractured Republican Party ahead of Tuesday's slate of winner-take-all primary elections, the confrontations between his legion of loyal supporters and protesters who accuse him of stoking racial hatred have become increasingly contentious, underscoring concerns about the divisive nature of his candidacy.

A North Carolina man was arrested after video footage showed him punching an African-American protester being led out of a Trump rally in that state on Wednesday. At that event, Trump recalled a past protester as "a real bad dude."

"He was a rough guy, and he was punching. And we had some people — some rough guys like we have right in here — and they started punching back," Trump said. "It was a beautiful thing."

At Trump's rally earlier Friday in St. Louis, he was repeatedly interrupted by protesters. Police there charged nearly three dozen people with general peace disturbance and one person with assault.

Texas Sen. Ted Cruz, second in delegates to Trump in the GOP race, said late Friday that the billionaire has created "an environment that encourages this sort of nasty discourse."

"When the candidate urges supporters to engage in physical violence, to punch people in the face, the predictable consequence of that is that is escalates," Cruz said. "Today is unlikely to be the last such incidence."

In a telephone interview after postponing his event in Chicago, Trump said he didn't "want to see people hurt or worse" at the rally, telling MSNBC, "I think we did the right thing."

But Chicago police said they had sufficient manpower on scene to handle the situation and did not recommended Trump cancel the rally. That decision was made "independently" by the campaign, said police spokesman Anthony Guglielmi.