Republican frontrunner Donald Trump refused to condemn supporters who were caught in a video attacking protesters at another one of his rallies. The video showed Trump’s campaign manager Corey Lewandowski apparently grabbing a protester while another was being beaten up.

Trump dismissed that his supporters have done anything wrong and also defended Lewandowski in an interview on ABC’s “This Week” on Sunday. He also refused to take back his warning to the Republican party on possible riots if he is denied the party’s nomination.

“I don’t know what’s going to happen, but I will say this, you’re going to have a lot of unhappy people,” he said,” the quoted him as saying. “I don’t want to see riots, I don’t want to see problems. But you’re talking about millions of people.”

The video showed Trump’s supporter, Tony Pettway, attacking a protester is an American flag t-shirt with a placard that read “Trump is Bad for America.” Pettway was arrested at the scene and charged with assault.

Trump blamed the protesters calling them “professional agitators” for the violence in the rallies.

“These are professional agitators and I think that somebody should say that when a road is blocked going into the event so that people have to wait sometimes hours to get in, I think that’s very fair and there should be blame there, too,” Trump told the ABC News’ George Stephanopoulos. “At what point do people blame the protesters?”

Although the video showed Lewandowski standing right next to the security guard who grabbed one of the protesters, Trump’s spokesperson said that he did not touch the protester.

“Corey Lewandowski was speaking with a protester at today’s rally in Tucson, Arizona when the individual he was speaking with was pulled from behind by the man to Lewandowski’s left,” the spokesperson wrote in an email, as quoted by the CBS News. “The video clearly shows the protester reacting to the man who pulled him, not to Mr. Lewandowski. Mr. Trump does not condone violence at his rallies, which are private events paid for by the campaign.”