Fox News’ research unit advised colleagues against taking some claims made by the network’s top commentators regarding Ukraine at face value.

According to a Daily Beast report Thursday, an internal Fox News research briefing book criticizes contributor John Solomon — who plays an “indispensable role” in a Ukrainian “disinformation campaign,” according to the briefing — as well as frequent guests Rudy Giuliani, Victoria Toensing and Joe diGenova for amplifying and “spreading disinformation.”

Fox News senior political affairs specialist Bryan Murphy, who produces research for the network’s Brain Room division, reportedly created the 162-page document titled “Ukraine, Disinformation, & the Trump Administration.”

The Daily Beast notes that the briefing particularly takes aim at Solomon, a former opinion columnist for The Hill who has appeared on Fox News host Sean Hannity’s show, for his pieces that bolstered baseless claims about Ukraine’s government interfering in the 2016 U.S. presidential election.

“John Solomon played an indispensable role in the collection and domestic publication of elements of this disinformation campaign,” the Fox briefing book notes, according to the Daily Beast.

Murphy also wrote in the internal brief that Fox News employees need to be aware of Solomon’s alleged journalistic misdeeds, which include “non-disclosure of conflicts, use of unreliable sources, publishing false and misleading stories, misrepresentation of sources, and opaque coordination with involved parties.”

However, The Daily Beast noted that Solomon has continued making appearances on Fox News even after Lt. Col. Alexander Vindman, who listened in on the infamous July phone call between Trump and Ukrainian President Volodymyr Zelensky, testified in the impeachment inquiry that “all of the elements” in Solomon’s columns were “false.” Solomon’s most recent appearance on the network happened last Friday on Laura Ingraham’s show.

The briefing book was first publicly flagged by former freelance Fox News producer Marcus DiPaola in a Wednesday tweet.

When asked for comment on the internal brief, Mitch Kweit, senior vice president of the Brain Room, told TPM in a statement Thursday that “the research division of Fox News produces a briefing book for all major stories, which serves as a standing collection of extensive data on major topics for internal use by all those in editorial functions.”

“The Ukraine briefing book is nothing more than a comprehensive chronological account of what every person involved in the Ukraine controversy was doing at any identifiable point in time, including tracking media appearances of major players who appeared on Fox News and in many other outlets,” Kweit said in a statement shared with TPM. “The 200 page document has thousands of data points and the vast majority have no relation to Fox News — instead it’s now being taken out of context and politicized to damage the network.”

Read The Daily Beast’s report here.