A protester leapt over a barricade, jumping into the security buffer surrounding the stage at the US Republican presidential front-runner Donald Trump’s rally in Dayton, Ohio on Saturday.
The man, Thomas Dimassimo, was stopped by several US Secret Service agents and other officers.
"I was ready. I don't know if I would have done well but I would have been out there fighting, folks," Trump told a rally later in the day. He said the man "was looking to do harm.”
He called for the arrest of protesters at his rally in Kansas City, Missouri, where his speech was repeatedly disrupted by demonstrators.
"This guy should be in jail right now. He shouldn't be out. This guy should be in jail. He should be in jail," he said.
Montgomery County Sheriff, Phil Plummer, says that Thomas Dimassimo of Fairborn, Ohio, has been charged with inducing panic and disorderly conduct.
Trump went on to finish his speech after the man was arrested, but the incident increased tension after his Chicago rally was abandoned a day ago for safety reasons.
Trump also claimed Dimassimo - a 22-year-old anti-racism activist according to the Dayton Daily news website - was “ISIS [DAESH] or ISIS [DAESH] related."
He has also described the Chicago clashes as a "planned attack," blaming "our communist friend," the self-described socialist Bernie Sanders from the Democratic Party, who has urged Trump to act against violence.
"As is the case virtually every day, Donald Trump is showing the American people that he is a pathological liar. Obviously, while I appreciate that we had supporters at Trump's rally in Chicago, our campaign did not organise the protests," Sanders replied.
Saturday's campaign stops came three days ahead of key elections in five states - Florida, Illinois, Missouri, North Carolina and Ohio - expect to further the Republican field.
It will be a make or break test for Florida Senator Marco Rubio and Ohio Governor John Kasich.
Trump is also seeking victories that might give him an almost insurmountable lead in the nomination, after he was badly defeated on Saturday in Washington DC and Wyoming.
Rubio earned 37.3 of the vote and John Kasich got 35.5 in the capital, while Texas Senator Ted Cruz won 66.3 percent of the votes in the western state of Wyoming.
Overall in the Republican Party, Trump has 460 delegates and Cruz follows him with 369. They need to reach 1,237 delegates to win the nomination.
Primaries in Florida and Ohio, where all Republican delegates are given to the winner of the popular vote instead of being awarded proportionally, will be particularly important.