When this week's Super Tuesday results came in, many Bernie Sanders supporters were surprised and disappointed by his lackluster performance.

His supporters took to social media to express their outrage, blaming fellow candidate Sen. Elizabeth Warren for not dropping out of the race and splitting critical progressive votes.

Supporters online viciously attacked Warren, calling her a "snake" and a "traitor" — some even began organizing online so that she would lose her US Senate seat for Massachusetts.

When asked about the attacks by MSNBC's Rachel Maddow, Bernie Sanders condemned the "ugly, personal attacks" against Warren.

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Bernie Sanders' most fervent supporters have built a grassroots progressive political movement since his 2016 presidential bid, showing up in throngs to his rallies.

But some are also notorious for viciously mobbing his opponents online — something the Vermont senator and 2020 presidential candidate has repeatedly denounced.

And after Sander's lackluster Super Tuesday performance, some of his most dogged backers directed their outrage at his fellow progressive candidate, Sen. Elizabeth Warren, sending a barrage of hateful messages and urging her to drop out of the race and endorse him.

In an interview with MSNBC's Rachel Maddow on Wednesday — before Warren dropped out of the race — Sanders was once again forced to address the more insidious side of his fan base. Sanders condemned them.

"We don't need ugly, personal attacks against Sen. Warren, or anyone else for that measure," Sanders said.

Sens. Bernie Sanders and Elizabeth Warren during the first night of the second presidential debate in Detroit, Michigan. Lucas Jackson/Reuters

Sanders noted that he hoped to encourage fans to have "vigorous debates" about issues online, instead of lambasting his opponents.

Maddow asked Sanders about the "big distance" between his "congeniality" with Warren and the vitriol directed at his opponent online.

She pointed to Sanders supporters who sent her snake emojis and called her a traitor. Some believed that Warren split up the progressive vote, contributing to his disappointing performance. Some Sanders fans went as far as organizing online so that she would lose her US Senate seat in Massachusetts, Maddow said.

The presidential candidate responded that he was "absolutely aghast" and "disgusted" with their aggression online and condemned their behavior.

Sanders acknowledged that he had a "cordial" conversation with Warren as she reassessed her candidacy, but did not discuss the details of their discussion.

Sanders faced similar problems in the 2016 election

This isn't the first time that Sanders had to address the aggression of some of his base. In 2016, Sanders addressed a sect of over-zealous supporters known as the "Bernie Bros" who gained notoriety for making sexist, derogatory remarks about Democratic presidential rival Hillary Clinton.

Throughout his 2020 bid, Sanders once again has had to reckon with the vitriol his supporters have spewed in his name — many believe that their aggression has ironically hurt Sanders' campaign overall.

Later in the interview, Maddow raised questions about whether the hostility from his base had ruined the prospects of Warren and Sanders working together in the future — specifically in a possible Sanders administration.

FILE - In this Feb. 26, 2020 file photo Democratic presidential candidate Sen. Elizabeth Warren, D-Mass., speaks at the National Action Network South Carolina Ministers' Breakfast in North Charleston, S.C. (AP Photo/Matt Rourke) Associated Press

The Vermont Senator refuted the idea, that at the end of the day, they both support the same policies, including Medicare for All, raising the minimum wage and canceling student debt despite having "major nuances" on the issues.

"Essentially she has run her campaign in the way that we have: taking on powerful corporate interests and representing working families in this country — something that is long overdue," Sanders told Maddow.

Now that Warren has dropped out of the presidential race, many are speculating who she will decide to throw her support behind for the remainder of the primary — and if she could become a vice presidential pick for either candidate.

When asked if he would consider Warren, however, Sanders kept his response vague and claiming that it was too early to have the conversation.

"I have a lot of respect for Senator warren and would love to talk to her about what kind of role she can have in our administration," he replied.