President Donald Trump on Tuesday fired the Department of Homeland Security official who had rejected Trump's claims of widespread voter fraud.

Trump announced on Twitter he was firing Chris Krebs, the director of the Cybersecurity and Infrastructure Security Agency, and directly tied it to Krebs' statement that said there "is no evidence that any voting system deleted or lost votes, changed votes, or was in any way compromised."

"The recent statement by Chris Krebs on the security of the 2020 Election was highly inaccurate, in that there were massive improprieties and fraud," Trump said in a tweet before repeating multiple baseless conspriacy theories about the election. "Therefore, effective immediately, Chris Krebs has been terminated as Director of the Cybersecurity and Infrastructure Security Agency."

CNN reported that Krebs, who ran the cyber arm of the Department of Homeland Security, expected to be fired.

In the lead-up to the election, Krebs had often quietly disputed the President's repeated false claims about mail-in ballots but went out of his way to not get drawn into criticizing his boss for spreading lies.

But in the days that have followed, Krebs has adopted a more forceful approach regularly posting on Twitter -- often with blaring red siren emojis -- fact checks of the claims and conspiracy theories being pushed by Trump, his allies and supporters around the country.

Krebs has been responsible for a widely praised revamp of the department's cybersecurity efforts and increasing coordination with state and local governments, as the first director of CISA. He served as one of the most key federal national security officials that oversaw an election that by all accounts went very smoothly.

Foreign adversaries were not able to affect any of the votes, CISA said, and it was "the most secure election in American history," according to them and the wider group of public and private election officials. That was the statement for which the President decided to fire Krebs on Tuesday evening.

Krebs kept up the fact check of the President's conspiracy-mongering until the final hours of his tenure, tweeting earlier Tuesday that claims of manipulation of election systems "either have been unsubstantiated or are technically incoherent." He was quoting from a letter signed by 59 election specialists that also said that "anyone asserting that a US election was 'rigged' is making an extraordinary claim" and called them "alarming assertions."

Firing Krebs, a US official previously told CNN, would "cross a red line" and set off alarm bells throughout the national security apparatus.

Still, his dismissal comes after several of the Pentagon's most senior civilian officials were replaced with officials perceived as loyal to the President, and reports of Trump's increasing frustration with CIA Director Gina Haspel.

text by Kaitlan Collins and Paul LeBlanc, CNN