Secret Service agents rushed on stage to protect US Republican presidential frontrunner Donald Trump during a disturbance at a rally, a day after rowdy protests shut down his event in Chicago.
Trump briefly ducked at the podium and four Secret Service agents scrambled to surround him after a man charged the stage at Dayton International Airport in Ohio on Saturday.
Agents then grabbed the man, dressed in a black tee shirt and jeans, and hauled him away.
His motivation was not immediately clear, and Trump went on to finish his speech, but the incident further increased tension after Trump's Chicago rally was abandoned amid chaotic scenes on Friday.
Disruptions at a rally on Saturday afternoon in Cleveland were quickly contained as Trump blamed them on Democratic candidates Bernie Sanders and Hillary Clinton.
Several hundred protesters were awaiting Trump's arrival at an evening event in Kansas City.
Trump's Republican rivals have hurled scorn at the New York billionaire, saying he helped create the nervous atmosphere that is now sweeping the race for the White House with his fiery rhetoric.
Trump blamed Sanders supporters for the incidents in Chicago, where scuffles broke out between protesters and backers of the real estate magnate. He called the US senator from Vermont "our communist friend".
The scenes in Chicago follow a series of recent incidents of violence at Trump rallies, in which protesters and journalists have been punched, tackled and hustled out of venues, raising concerns about degrading security leading into the November 8 election.
"All of a sudden a planned attack just came out of nowhere," Trump said in Dayton, describing the events in Chicago. He called the protest leaders there "professional people".
Sanders hit back, describing Trump as "a candidate that has promoted hatred and division".
President Barack Obama told a fundraising event in Dallas, Texas, that political leaders "should be trying to bring us together and not turning us against one another".
Republican candidate US Senator Marco Rubio bemoaned the state of the presidential race, saying it had "become reality television".
"Last night in Chicago, we saw images that make America look like a Third World country," Rubio said, reminding supporters the stakes on Tuesday are high.
"If Donald Trump is our nominee, it will fracture the Republican Party," Rubio added.
