Days after calling on the US government to break up Facebook, one of the company’s co-founders amplified his concerns over the level of Mark Zuckerberg’s sway across the social media empire and its billions of users.

“Zuckerberg has too much power — near-unilateral power,” Chris Hughes, 35, who started Facebook with Zuckerberg when they were students at Harvard University, said in an interview to air Sunday on CNN’s “Fareed Zakaria GPS.”

“We all make mistakes, but I think that in his case it is different because there is no accountability for those mistakes,” Hughes said, according to a transcript provided by CNN.

Hughes thrust himself into the center of a debate over how Washington should regulate the social media giant when he penned a May 9 op-ed in the New York Times calling Facebook a monopoly that never should have been allowed to buy Instagram and WhatsApp. Many observers already expect the Federal Trade Commission to slap the company with a fine of as much as $5 billion as part of a settlement.

But during his interview with CNN, Hughes said the company’s issues run far deeper than any one scandal. The problems, he said, stem in part from a lack of accountability for Zuckerberg and a board that’s generally unable to check the billionaire chairman and chief executive.