(CN) - Republican front-runner Donald Trump said Saturday morning organized "thugs" violated his First Amendment right to free speech by causing the cancellation of a campaign rally the night before in Chicago.
In a post on his verified Twitter account, Trump dismissed the thousands who turned out to protest his appearance ahead of the Illinois primary, saying "The organized group of people, many of them thugs, who shut down our First Amendment rights in Chicago, have totally energized America!"
At a rally in Vandalia, Ohio, Saturday morning, Trump continued the vitriol, blaming President Barack Obama for the fracas in Chicago.
"Our president has done so much to divide his nation," Trump said. "I call him the great divider."
At a later event, in Dayton, Ohio, Trump said protestors in Chicago had carried out "a planned attack" that was "professionally done."
During the same event, a man tried to rush the stage to get to Trump, but he was quickly apprehended by Secret Service officers. Trump was unhurt.
Chicago authorities estimated that as many as 4,000 of the 8,000-plus who turned up at the University of Illinois-Chicago Pavilion, and later spilled into the streets of the city, were intent on making sure the rally either never happened or went on accompanied by a loud voice of dissent.
As tensions escalated and conflicting factions shouted "Trump, Trump" and "Bernie, Bernie," the latter evoking the name of Sen. Bernie Sanders of Vermont, a Democratic candidate for president, an announcement was made that Trump, upon arriving in Chicago, met with law enforcement officials and that due to large number of protesters and the potential for violence, the rally could not go on.
As security personnel inside slowly emptied the hall, the Trump campaign released a statement that was played over the loudspeakers.
It said: "Mr. Trump just arrived in Chicago and after meeting with law enforcement has determined that for the safety of all of the tens of thousands of people that have gathered in and around the arena, tonight's rally will be postponed to another date."
The statement concluded: "Thank you very much for your attendance and please go in peace."
However, late Friday night acting Chicago Police Supt. John Escalante said his department had not been consulted and did not recommend Trump cancel the event.
"We assured the Trump campaign that we had more than adequate resources [at the event]" said Escalante, who went on to say that 200 officers had been assigned to work outside the venue long before the rally got out of hand.
The campaign responded with a written statement that said Commander George Devereux of the Chicago Police Department "was informed of everything before it happened. Likewise, Secret Service and private security firms were consulted and totally involved."
Outside the pavilion, hundreds chanted "Hey, hey, ho ho, Donald Trump has got to go" and "We shut Trump down."
Trump supporters responded with an angry chorus of "Build the wall," a reference to the candidate's pledge to build a wall between the United States and Mexico to stem the tide of illegal immigration, but the Chicago police quickly separated the two groups and maintained order.