Sanders issued a stinging rebuke on Saturday to the Republican presidential front-runner for noting that some of the protesters that disrupted Trump’s rally “represented Bernie, our communist friend."
The Democratic presidential candidate interpreted the remark as insinuating that he or his campaign had been directly involved in the protest.
“As is the case virtually every day, Donald Trump is showing the American people that he is a pathological liar,” Sanders said.
“Obviously, while I appreciate that we had supporters at Trump’s rally in Chicago, our campaign did not organize the protests.”
Trump had said at a campaign stop in Dayton, Ohio, on Saturday that Sanders supporters were among the protesters at Friday's rally. It is unclear if he meant to suggest that Sanders had organized the protest.
Chicago-based supporters of Sanders have, in fact, taken credit for playing an outsize role in the protests.
But Sanders argued that Trump’s bigoted rhetoric is what inspired the massive protests in Chicago and smaller demonstrations at previous campaign events.
“What caused the protests at Trump’s rally is a candidate that has promoted hatred and division against Latinos, Muslims, women, and people with disabilities, and his birther attacks against the legitimacy of President [Barack] Obama,” Sanders said.
“What caused the violence at Trump’s rally is a campaign whose words and actions have encouraged it on the part of his supporters,” Sanders added.
Trump responded on Twitter early on Sunday morning, insisting that Sanders was lying and suggesting he would soon retaliate by sending his supporters to protest Sanders' campaign events.
Sanders' Democratic presidential rival Hillary Clinton also condemned the unrest at the Trump rally in Chicago, though she did not mention the real estate mogul's name.
“The divisive rhetoric we are seeing should be of grave concern to us all,” Clinton said in a statement. “We all have our differences, and we know many people across the country feel angry. We need to address that anger together.”
“All of us, no matter what party we belong to or what views we hold, should not only say loudly and clearly that violence has no place in our politics, we should use our words and deeds to bring Americans together,” she added.
The former Secretary of State pointed to the successful campaign to remove the confederate flag from the South Carolina statehouse in the wake of the massacre at a predominantly black church in Charleston, South Carolina, as a “model we strive for to overcome painful divisions in our country.”
This story has been updated to include Donald Trump's tweet on Sunday morning.