A dozen senators called on the Federal Communications Commission to investigate Sinclair Broadcasting Group for distorting the news, and to pause its review of the pending acquisition of Tribune Media.

FCC Chairman Ajit Pai immediately shot down the request, saying it would conflict with his commitment to the First Amendment and freedom of the press.

Eleven Democratic senators and one independent, Bernie Sanders, took issue with Sinclair forcing local news anchors to read scripts. One that captured national attention denounced the “troubling trend of irresponsible, one-sided news stories plaguing our country,” and criticizing some members of the media who “use their platforms to push their own personal bias and agenda to control exactly what people think.”

A video created by the sports news site Deadspin stitched together a video of dozens of anchors parroting the same warnings about “false news,” underscoring Sinclair’s reach. John Oliver used video to update his report about Sinclair.

Senators said these must-run mandates from Sinclair harm free speech and turn local journalists into “mouthpieces for a corporate and political agenda.”

“We are concerned that Sinclair is engaged in a systematic news distortion operation that seeks to undermine freedom of the press and the robust localism and diversity of viewpoint that is the foundation of our national broadcasting laws,” the senators wrote.

The senators called on Pai to review whether Sinclair has violated the public interest obligation as a broadcaster and whether it’s fit to retain a license. They also urged the FCC to pause its pending examination of the $3.9 billion acquisition of Tribune pending the outcome of this process.

“We are concerned that if the Sinclair-Tribune merger continues without a thorough review of these new facts, Sinclair’s practices of news distortion will proliferate to even more local stations which Americans rely upon every day for fair and impartial news,” the senators wrote.

Sinclair owns 193 stations in 89 markets, which would expand to 223 stations reaching 72% of American households.

Pai said the FCC doesn’t have the authority to revoke licenses based on the content of newscasts.

“I understand that you disliked or disagreed with the content of particular broadcasts, but I can hardly think of an action more chilling of free speech than the federal government investigating a broadcast station because of disagreement with its news coverage,” Pai wrote.

The President is an unabashed fan of Sinclair, whose chairman reportedly told Trump during the 2016 campaign that the broadcaster was there “to deliver” his message.