President Donald Trump announced the firing of the official in charge of election cybersecurity, Christopher Krebs, in a Tuesday evening tweet. Before his firing, Krebs served as the first director of the Department of Homeland Security’s (DHS) Cybersecurity and Infrastructure Security Agency (CISA) after leading Microsoft’s policy work on cybersecurity and technology issues, according to his CISA bio.

In a Twitter response to being fired, Krebs said “Honored to serve. We did it right. Defend Today, Secure Tomorrow,” in a call to protect the 2020 election.

Although the presidential election was widely called for Joe Biden on November 7th, Trump has not conceded, and he and his allies have made numerous claims about supposed election fraud that aren’t backed up by evidence. Krebs, however, has actively debunked voting misinformation, such as denying a false conspiracy theory claiming that secret computer systems have been committing voter fraud.

Krebs himself reportedly expected to be fired, according to a November 12th report from Reuters. And that same day, CISA released a statement signed by the members of the Election Infrastructure Government Coordinating Council Executive Committee backing him up, saying that there was “no evidence” that voting in the US “was in any way compromised” and calling the election “the most secure in American history.”

Trump fired him anyway.

“Chris Krebs is an extraordinary public servant and exactly the person Americans want protecting the security of our elections,” Sen. Mark Warner (D-VA), vice chairman of the Senate Select Committee on Intelligence, said in a statement. “It speaks volumes that the president chose to fire him simply for telling the truth.”

“Director Krebs is a deeply respected cybersecurity expert who worked diligently to safeguard our elections, support state and local election officials and dispel dangerous misinformation,” Nancy Pelosi, Democratic House speaker, said in a statement. “Yet, instead of rewarding this patriotic service, the President has fired Director Krebs for speaking truth to power and rejecting Trump’s constant campaign of election falsehoods.”

Krebs was nominated for his former post by Trump in June 2018, and joined the DHS to advise on cybersecurity issues in 2017.

Update November 18th, 5:11AM ET: Added statements from Warner, Pelosi, and Krebs.