New disturbance at Trump rally as crucial Republican contests near

By William Philpott DAYTON, Ohio (Reuters) - Secret Service agents rushed on stage to protect U.S. Republican presidential front-runner Donald Trump during a disturbance at a rally on Saturday, 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. 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 U.S. 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 Nov. 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." "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 organize the protests." 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." Former Secretary of State Clinton drew criticism for releasing an initial statement that did not mention Trump by name and tied violent campaign events to a shooting in a South Carolina black church last year that left 9 people dead. While campaigning in St. Louis, Missouri, on Saturday, Clinton criticized Trump directly for "ugly, divisive rhetoric" that encourages aggression and violence. CRUCIAL PRIMARIES The months-long Republican race may be coming to a head at nominating contests on Tuesday where Trump is seeking victories that might give him an almost insurmountable lead for the nomination. Primaries in Florida and Ohio will be particularly important since they are winner-take-all states, where all Republican delegates are given to the winner of the popular vote instead of being awarded proportionally. It will be a make-or-break day for Republican candidates John Kasich, the governor of Ohio, and U.S. Senator Marco Rubio of Florida, who both must win their home states to forge a credible path forward. Rubio bemoaned the state of the presidential race during a Saturday event in Pinellas County on Florida's central Gulf Coast, 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. Kasich told journalists before a campaign event in Cincinnati, Ohio, that Trump had created a "toxic environment." "And that toxic environment has allowed his supporters, and those who seek confrontation, to come together in violence," he said. In a statement, Republican candidate U.S. Senator Ted Cruz of Texas called the Chicago incidents "sad." Trump has drawn fervent support as well as criticism for his calls to build a wall along the U.S.-Mexico border and to impose a temporary ban on Muslims entering the country. His rallies often attract small groups of protesters, but Friday's was the first at which there may have been as many protesters as supporters. Vanderbilt University political scientist John Geer said that the tension on display at Trump's events are a proxy for what is going on in the electorate writ large. "People have strong reactions to Donald Trump," Geer said. "They are playing out in the voting booth and they are also playing out at these events." Geer said the cancellation would likely embolden Trump's supporters - an idea floated by Trump in several television interviews. In minor nominating contests on Saturday, Clinton won the Northern Mariana Islands and Republican Cruz won Guam, according to television networks. (Additional reporting by Tim Reid in Cincinnati, Alex Dobuzinskis in Los Angeles, Kevin Murphy in Kansas, Catherine Koppel in Chicago, and Ian Simpson, Idrees Ali and Amanda Becker in Washington.; Editing by Alistair Bell and Sandra Maler)