Cambridge Analytica whistleblower Christopher Wylie said Facebook Inc. Chief Executive Officer Mark Zuckerberg engaged in "a spectacle of nonanswers" in testimony before U.S. and European lawmakers that would increase the chances the social network will face regulation and further harm the trust of its users.

Speaking at the Bloomberg Sooner Than You Think technology conference in Paris, Wylie expressed dismay that Zuckerberg has rebuffed invitations to appear before the U.K. Parliament committee investigating Cambridge Analytica's misuse of Facebook user data, and the role the consulting firm may have played in Britain's 2016 EU referendum.

"Mark Zuckerberg continues to reject the invitation from the one committee that will actually ask tough questions and won't let him get away with 'I'll get back to you, I'll get back to you, I'll get back to you,' " Wylie said.