CNN has refused to air a campaign advertisement for President Donald Trump targeting former Vice President Joe Biden, saying claims in it have been proven “demonstrably false.”

The ad features a narrator repeating debunked claims that Biden had blocked an effort to investigate his son’s work at a Ukrainian energy company. It also claims Democrats want to “steal the election.”

The commercial also attacks various television news personalities including CNN’s Don Lemon, Chris Cuomo and Jim Acosta, and MSNBC’s Rachel Maddow.

A spokeswoman for CNN said in a statement, “CNN is rejecting the ad, as it does not meet our advertising standards. Specifically, in addition to disparaging CNN and its journalists, the ad makes assertions that have been proven demonstrably false by various news outlets, including CNN.”

The ad has run on Fox News, MSNBC and other cable outlets. A spokesman for MSNBC, which is owned by Comcast’s NBCUniversal unit, declined comment. NBCUniversal is also the parent company of NBC News.

The Daily Beast first reported that CNN rejected the ad.

The ad is part of a broader push by Trump to counter an impeachment inquiry that is investigating his efforts to pressure Ukraine to investigate Joe Biden. The ad has been posted on various digital platforms including Trump’s Twitter account, where it had received more than 11.9 million views as of Thursday.

Tim Murtaugh, Trump’s campaign communications director, confirmed the ad is a national TV buy and criticized CNN for its decision.

“Our ad is entirely accurate and was reviewed by counsel, and CNN wouldn’t even describe to us what they found objectionable,” Murtaugh said.

The 2020 election is expected to trigger a flood of political ad spending on local and national TV. The Trump campaign and various committees close to the president have already raised more than $308 million in 2019.

Greg D’Alba, former chief operating officer at CNN and now chief executive of sentiment tracking firm 30dB, said he expected the rhetoric of political ads to continue to coarsen.

“This is a new world that will include ever-increasing trash talk on both sides,” D’Alba said. “The media will make decisions that will protect their brands. Unfortunately, they are no longer reporting the news but part of the news story.”