Billionaire Democratic donor Tom Steyer claims Fox News breached its contract by yanking his ads calling for President Trump's impeachment.

Brad Deutsch, an attorney for Steyer, said Fox News agreed Oct. 27 to air the ads for another week. Instead, Deutsch wrote in a letter to Fox, the network made the "baseless and unethical" decision to pull them early, calling it “a profound failure of journalistic integrity, a suppression of constitutionally protected speech, and likely a consequence of inexcusable political pressure.”

Jack Abernethy, co-president of Fox News, told Politico the decision to pull the ads was made over the "strong negative reaction" by Fox's viewers.

“Due to the strong negative reaction to their ad by our viewers, we could not in good conscience take their money,” Abernethy said in a statement.

The 60-second ad, which began airing in October, is part of a $10 million ad buy for the impeachment campaign. The ad says Trump has brought the U.S. to “the brink of nuclear war” with North Korea and goes after his firing of former FBI Director James Comey.

Trump subsequently went after Steyer on Twitter, calling him "wacky & totally unhinged."

Steyer’s lawyer took note of the tweet in the letter to Fox: “It is no coincidence that the Cancellation of the Advertisement, in the second week of its run, came on the heels of a tweet from President Trump, criticizing the spot and Mr. Steyer personally.”

In a statement last week, Steyer said: “millions of people have raised their voices in opposition to Donald Trump."

"If Fox News is siding with Trump and trying to silence us, they must be afraid of what we have to say. It shows no respect for democracy," Steyer said.