NPR has suspended Uri Berliner, the senior business editor who broke ranks and published an essay arguing that the nonprofit radio network had allowed liberal bias to affect its coverage.

Berliner was suspended by the network for five days, starting last Friday, for violating the network’s policy against doing work outside the organization without first getting permission.

Berliner acknowledged his suspension in an interview with NPR on Monday, providing one of the network’s reporters with a copy of the written rebuke. In presenting the warning, NPR said that Berliner had failed to clear his work for outside outlets, adding that he would be fired if he violated the policy again.

Berliner’s essay was published last week in The Free Press, a popular Substack publication.

The revelation of Berliner’s punishment is the latest aftershock to rattle NPR since Berliner published his essay. Employees at the public radio network were taken aback by Berliner’s public condemnation of the broadcaster, and several have said that they no longer trust him because of his remarks.

After Berliner’s essay was published, NPR’s new chief executive, Katherine Maher, came under renewed scrutiny as conservative activists resurfaced a series of years-old social media posts criticizing former President Donald Trump and embracing progressive causes. One of the activists, Christopher Rufo, has pressured media organizations into covering controversies involving influential figures, such as the plagiarism allegations against Claudine Gay, the former Harvard president.

NPR said on Monday that Maher’s social media posts were written long before she was named chief executive of NPR, and that she was not working in the news industry at the time. NPR also said that while she managed the business side of the nonprofit, she was not involved in its editorial process. Maher said in a statement that “in America everyone is entitled to free speech as a private citizen.”

Several NPR employees have urged the network’s leaders to more forcefully renounce Berliner’s claims in his essay. Edith Chapin, NPR’s top editor, said in a statement last week that managers “strongly disagree with Uri’s assessment of the quality of our journalism,” adding that the network was “proud to stand behind” its work.

This article originally appeared in The New York Times.