Bernie Sanders on Monday called Donald Trump a “pathological liar” amid the GOP presidential front-runner blaming the Vermont senator’s supporters for causing disruptions at his rallies.

“There was zero effort on the part of our campaign to organize — any disruption — at Trump’s” rallies, Sanders said at a MSNBC town hall. “And, you know, if you know me — I’ve never run a negative TV ad in my life.

“I know Marco Rubio and I know Ted Cruz and all these guys,” Sanders said. “But with Trump — what you are dealing with — and I say this without any joy. This guy’s a pathological liar,” Sanders said.

When moderator Chuck Todd pushed Sanders further on his criticism, the Vermont senator referenced an article that said Trump “never has any facts.”

Sanders blasted Trump for calling him a communist, saying it’s a “total, absolute, complete lie.”

“So it is very difficult dealing with some guy who lies all the time. And what I think Senator Rubio and many of us feel is this is a guy who’s inciting violence,” Sanders said.

Sanders also accused Trump for encouraging violence from his supporters.

“What I am disturbed about is we have a major candidate for president of the United States, Donald Trump, who is literally inciting violence among his supporters,” Sanders said.

Trump’s rally in Chicago last Friday was canceled due to safety concerns over massive protests. A protestor at an Ohio rally on Saturday was arrested and charged with disorderly conduct after charged the stage.

The real estate mogul has said he doesn’t condone the violence at his rallies.