ABC News Chief White House Correspondent Jonathan Karl knocked his CNN counterpart Jim Acosta in his new book about covering the Trump presidency.

In his memoir "Front Row at the Trump Show," Karl claimed that Acosta was "playing into the explicit Trump strategy of portraying the press as the opposition party."

"The surest way to undermine the credibility of the White House press corps is to behave like the political opposition," Karl wrote. "Don't give speeches from the White House briefing room."

At a gathering commemorating the release of the book, Karl told The Daily Beast: “Regarding Jim Acosta, to paraphrase Voltaire, I will defend to the death his right to report from the White House, but I have some issues with the style in which he has done so... We can be tough, we can call out things that are not true, we can be aggressive in our questioning, but I don’t think we should act like we are part of the resistance.”

TRUMP SPARS WITH JIM ACOSTA AT CORONAVIRUS BRIEFING: 'THIS IS WHY PEOPLE DON'T WANT TO LISTEN TO CNN ANYMORE'

"A sub-sub theme is those of us reporters make a mistake if they appear to be too much like an opposition to the president or the resistance," Karl similarly told the Washington Free Beacon. "That's not our job. We're not the opposition party. We're supposed to report and report aggressively on the president, on any president, but not to go over the top."

Karl also serves the president of the White House Correspondents' Association.

Acosta had another clash with President Trump at Monday's coronavirus press briefing.

"What do you say to Americans who are upset with you over the way you downplayed this crisis?" Acosta asked. He referenced earlier quotes from the president, including when Trump said roughly a month ago: "It's going to disappear. One day, it's like a miracle, it will disappear."

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Acosta added, "What do you say to Americans who believe that you got this wrong?"

The president fired back.

"Well, it will go away and I do want them to stay calm, and we are doing a great job," Trump responded. "If you look at those individual statements, they're all true. Stay calm, it will go away -- you know that it is going away, and... we're going to have a great victory. And, it's people like you and CNN that say things like that -- it's why people just don't want to listen to CNN anymore. You could ask a normal question."