Former US president Donald Trump is suing CNN for defamation and is seeking $475 million in punitive damages.
Mr Trump, a Republican, claims the network carried out a “campaign of libel and slander” against him.
Posting on his social media platform Truth Social, the former president accused CNN of becoming a “purveyor of disinformation, defamation and fake news, at a level which the American public, and indeed the world, will not even believe is possible”.
He said: “For years I have watched this take place, often in disbelief, but the time has finally come to hold CNN responsible and legally accountable for their wilful deception and defamatory statements made about me.”
The businessman's lawsuit claims CNN used its considerable influence as a leading news organisation to defeat him politically.
He filed the case at the US District Court in Fort Lauderdale, Florida.
CNN has declined to comment.
Mr Trump's 29-page lawsuit said CNN had a long track record of criticising him and had stepped up the criticism in recent months over fears he would run for president in 2024.
“As a part of its concerted effort to tilt the political balance to the left, CNN has tried to taint the plaintiff with a series of ever more scandalous, false and defamatory labels of 'racist', 'Russian lackey', 'insurrectionist' and, ultimately, 'Hitler',” the lawsuit claims.
The lawsuit lists several instances in which CNN appeared to compare Mr Trump, 76, to Adolf Hitler, including a January 2022 special report by host Fareed Zakaria that included footage of the German dictator.
Mr Trump, who in 2020 lost a re-election bid to Democrat Joe Biden, has not said whether he would seek re-election.
The former president said he would be filing lawsuits against other major media companies “in the coming weeks and months”, and that he could even take action against a congressional committee probing the attack on the US Capitol by his supporters on January 6 last year.
The lawsuit comes as the former president faces considerable legal woes, including a criminal investigation by the US Justice Department for retaining government records at his Mar-a-Lago estate in Florida after leaving office in January 2021.
Mr Trump was sued last month by New York state Attorney General Leticia James, who has accused him of lying to banks and insurers over the value of his assets.