Aamer Madhani

USA TODAY

BLOOMINGTON, Ill. — The day after U.S. Secret Service agents had to scurry to protect him from a protester rushing the stage at a rally, GOP front-runner Donald Trump on Sunday pulled a man out of the crowd to help him make a point about immigration.

Trump sought and received Secret Service agents' permission to allow a man on stage he spotted wearing a T-shirt with the handwritten message "Legal Immigrant for Trump."

"We want people to come into our country," said Trump, after spotting the man. "But they got to come legally like you, right?"

Trump then pulled the man on stage. The man, who identified himself as Alex Stypik, briefly spoke to the crowd and said that Trump, who has called for building a wall along the U.S.-Mexico border and faced criticism for once saying Mexico sends the U.S. its "rapists," is not properly understood on the issue.

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Stypik said that his father brought him to the U.S., when he was 5 and did it "by the book."

"People spill out their guts to come here legally," Stypik said.

Trump told the crowd that he had never met the man before that moment.

"I didn't think they were going to say yes," Trump said of the Secret Service agents. "Look at him. He's a tough looking guy."

The rally in Downstate Illinois comes as Trump campaign events have been marked by increasingly tense skirmishes between the real estate mogul's supporters and opponents in the lead up to a series high-profile primaries in Florida, Illinois, Missouri, North Carolina and Ohio on Tuesday.

Trump: I'm not responsible for violence at rallies

On Friday, Trump canceled an appearance in Chicago after it became apparent that hundreds of anti-Trump protesters had filled the arena on the campus of the University of Illinois at Chicago.

Skirmishes erupted between protesters and Trump supporters and at least five people were arrested in and around the aborted Chicago event. Earlier that same day, police arrested 32 people at rally in St. Louis

Kansas City Police deployed pepper spray twice outside a Trump rally in downtown arena on Saturday night to deal with protesters who police said “refused to follow the law.” That incident came after Secret Service tackled a man who rushed a stage as Trump delivered a speech earlier in the day in Vandalia, Ohio.

Sunday's rally at an airfield in this community, which is home to the Illinois State University campus, went off with relatively few disruptions. Several protesters were ejected throughout the rally, but it did not have the level of tension that Trump's gatherings have had in recent days.

Trump: I'm not responsible for violence at rallies

Trump repeated his assertion that the protesters, who try to disrupt his rallies, are backers of Democratic presidental candidate Bernie Sanders. Some, he said, act out violently and have to be treated "roughly."

"Can you imagine if some of you went to a Bernie rally," Trump told the crowd.

In recent days, Trump’s GOP rivals — Sen. Ted Cruz, Sen. Marco Rubio and Gov. John Kasich — have all said that Trump holds at least some responsibility for the atmosphere at his campaign events, which have included his supporters assaulting protesters and comments from Trump suggesting that the demonstrators sometimes need to be treated roughly.

Rubio and Kasich, who both had previously pledged to support whoever emerges as the GOP nominee, on Saturday suggested they may abandon that promise if Trump, the current front-runner, wins the nomination.

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Kasich, who is knotted in a close race with Trump for the 66 delegates in his home state of Ohio, charged that Trump has created a “toxic environment” that would make it “extremely difficult” to support if he emerges as the nominee.

Don Brucker, 46, who described himself as Republican/Libertarian-leaning voter, said that Kasich and Rubio are treading into dangerous territory that will alienate voters like him.

“I am very disappointed in those guys,” said Brucker, of Lexington, Ill.. “If the people elect Trump, then he should be supported. I wouldn’t say I’m pro-Trump, but I sure would say I’m pro anti-establishment. What those candidates are talking about is going against the will of the people.”

Michael Johnson, a Trump supporter from nearby Normal, Ill., discounted the criticism from Cruz, Kasich and Rubio toward his candidate, saying that Trump’s appeal has been enhanced by his lack of filter.

“They are worried about being politically correct,” said Johnson, 51, who attended Sunday’s rally with his son and their friends. “They are worried about hurting someone’s feelings with what they say. Trump is saying the things that are on everyone’s mind but are too afraid to say. I don’t agree with some of the comments he’s made, but it’s an expression of the anger that Americans have with what’s going on with politics.”

Follow USA TODAY Chicago correspondent Aamer Madhani on Twitter: @AamerISmad

Elections 2016 | USA TODAY Network