The presidential campaign of Democrat Bernie Sanders effectively declared war on the Democratic National Committee Friday, condemning as unfair a punishment the party doled out after discovering that Sanders staffers had inappropriately accessed sensitive information from Hillary Clinton’s campaign held by the DNC.

The DNC maintains a master voter file, which campaigns supplement with their own information. On Wednesday, a vendor error created a security breach that several Sanders staffers, including its top data official, exploited to access valuable Clinton campaign data. The DNC responded by barring the Sanders campaign from the database entirely, which includes data generated by the campaign itself.

Close video Fired Sanders campaign staffer speaks out Josh Uretsky, fired Sanders campaign staffer, is interviewed by MSNBC’s Steve Kornacki with his perspective on the controversy following Clinton campaign data being accessed by the Sanders campaign during a DNC firewall failure. Josh Uretsky, fired Sanders campaign staffer, is interviewed by MSNBC’s Steve Kornacki with his perspective on the controversy following Clinton campaign data being accessed by the Sanders campaign during a DNC firewall failure. share tweet email Embed

Saying the national party violated its pledged neutrality with the punishment, Sanders campaign manager Jeff Weaver threatened to sue the DNC in federal court and accused the national party of “trying to help the Clinton campaign” with “our data [that] has been stolen by the DNC.”

“Rather incredibly, the leadership of the DNC has used this incident to shutdown our access to our own information. This is the lifeblood of our campaign,” Weaver said at a press conference Friday in Washington. “By their action, the leadership of the DNC is now actively attempting to undermine our campaign. This is unacceptable.”

The lockout has had sweeping ramifications for the Sanders campaign, effectively bringing to a halt the their entire field operation. Sanders quickly fired his chief data official, and more punishments may come, but it’s unclear when the conflict will be resolved and when the campaign will be allowed back in to the database.

“This is taking our campaign hostage,” Weaver said.

As Weaver was speaking, the DNC released a new statement from Chairwoman Debbie Wasserman Schultz accusing the Sanders campaign of “inappropriately and systematically” accessed Clinton data. “I have personally reached out to Senator Sanders to make sure that he is aware of the situation. When we receive this report from the Sanders campaign, we will make a determination on re-enabling the campaign’s access to the system,” she said.

RELATED: Documents show Sanders staffers breached Clinton voter data

Appearing on MSNBC earlier in the day, Wasserman Schultz said the campaign downloaded and exported the data, in contradiction to earlier Sanders statements. (The tech vendor, NGP VAN, said the Sanders official “was able to search by and view, but not export or save or act on” the data.

It’s a dramatic eruption of tensions that have simmered for months between the DNC and supporters of Sanders and long shot candidate Martin O’Malley. And it comes just over 24 hours away from the party’s final presidential debate of the year, which itself has generated controversy.

When Clinton and Sanders meet onstage in Manchester, New Hampshire Saturday night, the mood will be tenser than ever as acrimony between the campaigns reaches new heights following the illicit data breach.

Already, Sanders allies alleged the DNC limited the number of debates and their timing – including this one on the final weekend before Christmas – to protect Clinton.

And in the center of it all is Wasserman Schultz, who effectively referees the party’s nominating contest. Anti-Clinton forces have long accused her of being in the tank for the Democratic front-runner, noting she served as national co-chair of Clinton’s 2008 campaign.

But the dust-up over the data breach, the most explosive controversy to hit the Democratic primary thus far, has solidified drawn battle lines, with Sanders going to war against the DNC and the Clinton campaign with the army it has, a fairly rag tag group of liberal organizations.

Sanders’ relationship with the Democratic Party is fragile to begin with. He is the longest serving independent in the history of Congress and has been highly critical of the party in the past, before officially joining it this year to run for president. While he caucuses with the Democrats in the Senate and agrees ideologically with the party on virtually every issue, he was proud to say he was not beholden to any party bosses. That served him well, but also meant he has not engaged in the kind of party building activities typically requested of partisan politicians.

Allies tried to blame the DNC and its vendor, NGP VAN, for the breach, instead of Sanders. MoveOn.org said the DNC had “failed” to keep data safe and that locking Sanders out of the database was “unnecessary and misguided.”

Charles Chamberlain, the executive director of the group Democracy for America, which endorsed Sanders Thursday, called on the DNC to reverse its decision “before the committee does even more to bring its neutrality in the race for President into question.” Dan Cantor of the Working Families Party, which endorsed Sanders last week, said the DNC had to “take their thumbs off the scale.”

“Last week, the Working Families Party chose our candidate, and today, it looks like the DNC has chosen theirs,” he said.

Already on social media, Sanders fans seemed ready to go to the barricades, seeing the move as an attempt by the political establishment to squash an insurgent threat. Using the hashtag #StormTheDNC, supporters have shared the number for the DNC switchboard so supporters can express their outrage, while some supporters on Reddit are calling for stepped up donations to Sanders’ campaign.

National Nurses United, a nurses union that has endorsed Sanders, plans to stage a protest outside Wasserman Schultz’ congressional office in Florida. Executive Director RoseAnn DeMoro said the DNC’s decision to lock out Sanders “continues an anti-democratic pattern by the DNC to derail the growing grassroots momentum of the Sanders campaign and the millions of Americans who support it.”

It’s a natural card for Sanders and his allies to play, and it will undoubtedly rally supporters to their cause – but it may win over few others. Regardless of whether the DNC’s punishment was too harsh, it does not change the fact that senior Sanders campaign officials worked to improperly access Clinton’s proprietary data, and evidence suggest they did so in a systematic way.

Instead, the battle is likely to only harden either side’s distrust of the other as the candidates head into the home stretch of the primary.

This story has been updated.