This post has been updated.

The campaign manager for Sen. Bernie Sanders (I-VT) held a fiery press conference on Friday afternoon where he threatened to sue the Democratic National Committee for blocking the campaign’s access to its voter files and accused Democratic officials of trying to “sabotage” Sanders’ presidential bid and help Hillary Clinton’s campaign.

Sanders campaign manager Jeff Weaver announced at a Friday press conference that the campaign may file a federal lawsuit against DNC later that day. He accused the DNC of holding the campaign’s data “hostage.”

“They are not going to sabotage our campaign,” Weaver said.

The DNC suspended the Sanders campaign’s access to its voter data on Thursday after campaign staffers inappropriately accessed confidential information maintained by Hillary Clinton’s campaign. The campaigns were briefly able to view each other’s voter files during a brief software glitch on Wednesday.

Weaver accused the DNC of working to undermine the Sanders campaign in an attempt to bolster Hillary Clinton’s presidential bid.

“It is our information and the information of all of these volunteers and the people who support our campaign, not the DNC’s. In other words, by their action, the leadership of the Democratic National Committee is now actively attempting to undermine our campaign,” Weaver said. “This is unacceptable. Individual leaders of the DNC can support Hillary Clinton in any way they want, but they are not going to sabotage our campaign, one of the strongest grassroots campaigns in modern history.”

Later in the press conference, a reporter asked Weaver if he believed the DNC was trying to help Clinton’s campaign by suspending the Sanders campaign’s access to voter data.

“I don’t know the motivation of every single person of the DNC, but I think if you look at a pattern of conduct, we obviously have concern about the Saturday night debate schedule and its impact on the ability of campaigns to get their message out. Clearly in this case it looks like they are trying to help the Clinton campaign,” Weaver said.

“I’m sure there are people within the democratic establishment who are not happy about the overwhelming success Sen. Sanders is having all across this country,” he added. “To do that, we need our data which has been stolen by the DNC.”

Weaver blamed the DNC and its vendor that manages the committee’s voter files, NGP VAN, for allowing Sanders staffers to access data gathered by other campaigns. He said that the campaign experienced a similar issue in October. Weaver said that the Sanders campaign is “confident” that some of its data was erroneously sent to another Democratic campaign at that time.

“On more than one occasion they have dropped the firewall between the data of competing democratic campaigns. This is dangerous incompetence,” Weaver said.

He added that it was irresponsible for Sanders staffers to view the Clinton campaign’s data. He said that one staffer was fired, and that the campaign is currently reviewing the emails and documents of other campaign employees who also may have conducted searches of other campaigns’ information.

The Associated Press and NBC News reported on Friday that four staffers of the Sanders campaign searched the Clinton campaign’s voter data. According to documents reviewed by NBC News, members of the Sanders campaign saved information from Clinton’s voter files.

When asked about this on Friday, Weaver said that “no data that I’m aware of was exported in a way that could be used by anybody.”

“We are running a clean campaign. We will beat secretary Clinton and everybody else in this campaign on the issues. We don’t need dirty tricks. That’s not how we run it here,” Weaver told reporters.

The campaign handed out a paper statement to reporters at the press conference: