Facebook may be in some pretty deep shit here.

A campaign finance reform group, accusing Facebook of being used as an “accomplice” in a Russian influence scheme, is calling on company chairman Mark Zuckerberg to reverse his position and publicly release “secretly-sponsored” Russian political ads that ran on its platform during last year’s presidential election.

“Facebook was secretly paid to host illegal political ads as part of an illegal foreign influence effort,” said the letter to Zuckerberg from Trevor Potter, president of the Campaign Legal Center and a former chairman of the Federal Election Commission.

“We are not aware of any federal law that would prohibit Facebook from making these ads public,” the letter to Zuckerberg continued. “[B]y hosting these secretly-sponsored Russian political ads, Facebook appears to have been used as an accomplice in a foreign government’s effort to undermine democratic self-governance in the United States. Therefore, we ask you, as the head of a company that has used its platform to promote democratic engagement, to be transparent about how foreign actors used that same platform to undermine our democracy.”

‘Accomplice’ is a pretty strong word.