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In a profile that Variety published on Zucker on Tuesday, the CNN chief said that competitors like Vice and BuzzFeed were not even worthy of being called journalistic outlets.
"I don't think Vice and BuzzFeed are legitimate news organizations," Zucker said, reportedly cracking a "mischievous" smile. "They are native advertising shops. We crush both of them. They are not even in our same class."
Despite Zucker's dismissal of his digital competitors, CNN has repeatedly relied on BuzzFeed's original reporting in its own broadcasts and write-ups.
During a town hall hosted by Anderson Cooper earlier this year, Cooper confronted Trump with revelations that he had supported the invasion of Iraq in 2002, which BuzzFeed discovered in an interview with radio DJ Howard Stern.
CNN has faced criticism this election cycle for providing a platform for the real-estate magnate's message, carrying many of his events live during the primaries. According to Variety, Zucker has an image of one of Trump's positive tweets about CNN framed on his office wall.
In a statement, BuzzFeed Editor Ben Smith chided CNN's coverage of Trump.
"The most important test of any news organization this year is its coverage of the 2016 presidential campaign. I'm happy to put our tough, fair coverage up against CNN's decision to turn its platform over to Jeff's friend Donald Trump," Smith said.
A representative for Vice did not immediately respond to a request for comment.