Sen. Bernie Sanders called his supporters who are refusing to get involved in the 2020 election because Joe Biden is the presumptive Democratic nominee "irresponsible."

Sanders dropped out of the presidential race and endorsed Biden's run against President Trump in recent days. However, his former national press secretary Briahna Joy Gray made it clear that she would not support the former vice president. When asked about the situation by the Associated Press on Tuesday, Sanders distanced himself from Gray.

"She is my former press secretary — not on the payroll," the Vermont senator said.

Paychecks for campaign staff stopped flowing on Tuesday, but severance checks will be distributed in May, and the staff will continue to receive healthcare benefits until November. Sanders said his supporters have a simple choice to make this fall.

“Do we be as active as we can in electing Joe Biden and doing everything we can to move Joe and his campaign in a more progressive direction? Or do we choose to sit it out and allow the most dangerous president in modern American history to get reelected?” he said. "I believe that it’s irresponsible for anybody to say, ‘Well, I disagree with Joe Biden — I disagree with Joe Biden! — and therefore I’m not going to be involved.’”

Gray has stirred controversy since Sanders ended his bid. When the former candidate endorsed Biden, Gray tweeted, "With the utmost respect for Bernie Sanders, who is an incredible human being & a genuine inspiration, I don't endorse Joe Biden. I supported Bernie Sanders because he backed ideas like #MedicareForAll, cancelling ALL student debt, & a wealth tax. Biden supports none of those."

She also speculated that Democrats may even be looking to "replace" the former vice president as the party's nominee.