Donald Trump called the protests that forced him to postpone a rally in Chicago on Friday a "planned attack" that "came out of nowhere."
Speaking to supporters in Dayton, Ohio, on Saturday, Trump said more than 25,000 people were registered for the rally at University of Illinois at Chicago Pavilion. Protests quickly broke out among some of those in attendance as people waited for Trump to speak.
"They were pouring into the arena," Trump said. "All of a sudden, a planned attack just came out of nowhere."
The organized group of people, many of them thugs, who shut down our First Amendment rights in Chicago, have totally energized America!
— Donald J. Trump (@realDonaldTrump) March 12, 2016
Trump said the protests were "very professionally done" and placed some blame on Vermont Sen. Bernie Sanders, saying some of the protesters were his supporters.
Trump said Sanders "should really get up and say to his people, 'stop.'"
Trump said he hadn't wanted to cancel the event but did so over safety concerns.
"We dealt with law enforcement at every level," Trump said. "It was determined that if we go in, it could cause really bad, bad vibes."
The Chicago Police Department said it had sufficient officers to handle any issues at the rally. Interim Chicago Police Superintendent John Escalante said the Trump campaign hadn't consulted with the department before calling off the event.
The clashes between protesters and his supporters, which Trump called "disgraceful," led to five arrests and two police officers being injured.
Before Trump spoke in Dayton on Saturday, Ohio Gov. John Kasich said the real estate mogul had created a "toxic environment."
"There is no place for this," he said. "There is no place for a national leader to prey on the fears of the people who live in our country."
Florida Sen. Marco Rubio sounded frustrated when asked if he would support Trump if he was the party's presidential nominee.
"I don't know," he said. "I already talked about the fact that [Hillary] Clinton will be terrible for this country the fact that you are even asking me that question -- I intend to support the Republican nominee, but it's getting harder every day."
Trump has courted criticism for remarks appearing to encourage violence against the protesters who have increasingly been disrupting his rallies. In St. Louis on Friday, he mocked those who interrupted his speech and were removed by police, telling them to "go get a job" and one to "go back to mommy."
"These are people that are destroying our country," he said at the time, adding, "You know part of the problem and part of the reason it takes so long is no one wants to hurt each other anymore and they’re being politically correct the way they take them out so it takes a little longer."
After his rally in Chicago was called off, Trump told Fox News the protesters there weren't directing their anger at him.
"This has a lot to do with jobs," Trump said. "It has a lot to do with the incompetent running of a country."
ABC News' Ben Gittleson in Cincinnati, Ohio, and Brad Mielke in Key Largo, Florida, contributed to this story.