(TNS) — Key officials at the U.S. Cybersecurity and Infrastructure Security Agency are stepping down or expecting to get fired from their roles as President Donald Trump continues to question the results of the Nov. 3 election, saying he was the victim of a fraudulent voting process.

Christopher Krebs, the head of CISA who has enjoyed bipartisan support for his role in helping run secure U.S. elections in 2018 and 2020, has told associates he expects to be dismissed, according to three people familiar with internal discussions.

Krebs' departure would follow the resignation of Bryan Ware, assistant director for cybersecurity at CISA, who resigned Thursday morning after about two years at the agency. In addition, Valerie Boyd, the assistant secretary for international affairs at the Department of Homeland Security, which oversees CISA, has also left, according to two other people.

CISA's profile has been raised over the past week because of its role in trying to stomp out election rumors, including unsubstantiated allegations that votes have been cast on behalf of dead people and that "secret" watermarks on ballots are helping the federal government audit illegal votes. That's put the normally under-the-radar agency in conflict with the president's unsubstantiated claims of "massive fraud" in voting that he says is costing him a second term.

Officials at CISA declined to comment on Ware's departure and didn't respond to requests for comment about Krebs' expectation that he would be fired. Agency officials didn't immediately respond to a request for comment about Boyd.

"There are rumors the president may be cleaning house at CISA, with one high-level official reportedly asked to resign already. This is dangerous," Rep. Bennie Thompson, the chairman of the House Homeland Security Committee, said in a statement Thursday night.

The latest upheaval follows the departures of a number of cybersecurity officials critical to the U.S. effort to defend against foreign influence in elections.

Last year, Jeanette Manfra, who served as CISA's assistant director, announced she would step down, as did Amy Hess, who served as the executive assistant director of the Criminal, Cyber, Response and Services Branch of the FBI. In August, the State Department's top cyber policy official, Rob Strayer, left his government post as well.

It also comes amid a shakeup at the top of the Pentagon, where the secretary of defense and two key under secretaries have been replaced this week.

Under Krebs' direction, CISA has earned praise from officials and lawmakers in both parties.

"I completely support and endorse everything Chris Krebs is saying and doing" on election security, said Tom Bossert, who previously served as Trump's homeland security adviser and currently serves as president of the firm Trinity Cyber. "He has personally brought a lot of credibility to that office." He added that Krebs and CISA have offered a "significantly expanded set of tools and capabilities."

Michael Chertoff, former DHS secretary under President George W. Bush, said "the personnel at CISA and the director, Chris Krebs, they have been scrupulous."

As part of this work protecting the 2020 election in the U.S., Krebs sought to address the rampant disinformation creating distrust in the election process. CISA stood up a new website, called "Rumor Control" which provided detailed analyzes of false claims before and after Election Day, debunking widespread rumors in order to help voters sort fact from fiction.

Nathaniel Gleicher, who serves as Facebook's head of security policy and works on countering influence operations, thanked Krebs and the CISA on Thursday.

"I've said it before, and now seems like a good time to say it again: thank you to the @CISAgov leadership, including @CISAKrebs and many others, who have worked so tirelessly to keep our election safe and to ground our ongoing public debate in accurate information," he tweeted Thursday.

Ware didn't clarify in his resignation letter why he was leaving during what has turned out to be a tumultuous transition to the Biden administration.

"I came on board in October of 2018 with the commitment to then Secretary Nielsen to serve, certainly, through the election and I didn't anticipate serving in the second term," he said in an interview, referring to ex-Homeland Security Secretary Kirstjen Nielsen.

"You see that in elections, I think we did really well, partnering with local governments and the broader ecosystem to protect this election," Ware said.

Sen. Angus King, an independent from Maine who also serves as co-chair of the U.S. Cyberspace Solarium Commission, called Krebs' work with states on election security "amazing" in a recent press briefing with reporters.

"The state infrastructure, the registration rolls, the election rolls, voting machines, all of that, is much better, much stronger, much more resilient than it was four years ago," he said.

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