A senior business editor at National Public Radio has resigned after writing an essay for an online news site published last week accusing the outlet of a liberal bias in its coverage.

In a Wednesday post on John CaldwellX, Uri Berliner included a statement in what he said was his resignation letter to NPR President and CEO Katherine Maher.

"I am resigning from NPR, a great American institution where I have worked for 25 years," Berliner wrote in the post. "I don't support calls to defund NPR. I respect the integrity of my colleagues and wish for NPR to thrive and do important journalism. But I cannot work in a newsroom where I am disparaged by a new CEO whose divisive views confirm the very problems at NPR I cite in my Free Press essay."

On Friday, Berliner was suspended for five days without pay, NPR confirmed Tuesday, a week after his essay in the Free Press, an online news publication, where he argued the network had "lost America's trust" and allowed a "liberal bent" to influence its coverage, causing the outlet to steadily lose credibility with audiences.

Berliner's essay also angered many of his colleagues and exposed Maher, who started as NPR's CEO in March, to a string of attacks from conservatives over her past social media posts.

Dig deeper:NPR suspends senior editor Uri Berliner after essay accusing outlet of liberal bias

NPR reported that the essay reignited the criticism that many prominent conservatives have long leveled against NPR and prompted newsroom leadership to implement monthly internal reviews of the network's coverage.

Neither NPR nor Maher have not yet publicly responded to Berliner's resignation, but Maher refuted his claims in a statement Monday to NPR.

"In America everyone is entitled to free speech as a private citizen," Maher said. "What matters is NPR's work and my commitment as its CEO: public service, editorial independence, and the mission to serve all of the American public. NPR is independent, beholden to no party, and without commercial interests."

Contributing: Eric Lagatta, USA TODAY.