Democratic presidential candidate Bernie Sanders dodged a reporter's question Tuesday about alleged threats made by his supporters toward the chairwoman of the Nevada Democratic Party at the state's convention over the weekend.

Roberta Lange said she received death threats from Sanders supporters after some of the Vermont senator's delegates were declared ineligible at the convention. Someone left a voicemail saying she should be "hung in public execution."

Asked in Puerto Rico for a reaction, Sanders abruptly walked away from reporters without answering the question.

Michael Briggs, a Sanders spokesman, told The New York Times on Monday that while Sanders does not condone threats or violence, the Democratic Party should be "more welcoming" of Sanders supporters. And Democratic National Committee Chairwoman Debbie Wasserman Schultz released a statement calling for universal condemnation of the Sanders supporters' "troubling" attacks.

"We will be reaching out to the leadership of both of our campaigns to ask them to stand with the Democratic Party in denouncing and taking steps to prevent the type of behavior on display over the weekend in Las Vegas," Wasserman Schultz said. "There is no excuse for what happened in Nevada, and it is incumbent upon all of us in positions of leadership to speak out."

Top Democrats supporting Hillary Clinton have called on Sanders to drop out of the race, and some fear that the threatening behavior of some Sanders supporters could carry over to the Democratic convention in July.

Sanders released a statement later Tuesday afternoon in which he condemned "any and all forms of violence, including personal harassment of individuals," but did not apologize for the actions of his supporters. "At that convention the Democratic leadership used its power to prevent a fair and transparent process from taking place," he added, accusing Lange of acting inappropriately during the convention to stifle his chances.

—Andrew Desiderio