Facebook CEO Mark Zuckerberg apologized over a growing data scandal in an interview Thursday, telling CNN’s Laurie Segall that that the exposure of users’ data to political consulting firm Cambridge Analytica “was a major breach of trust,” and that he was “really sorry that this happened.” “We have a basic responsibility to protect peoples’ data,” Zuckerberg said in an interview on Anderson Cooper 360. Zuckerberg’s comments broke days of silence from the Facebook CEO following revelations that data mining firm Cambridge Analytica had obtained the personal data of 50 million Facebook users through third-party apps while working for Donald Trump’s presidential campaign. Facebook responded by banning the firm and its whistleblowing contractor Christopher Wylie, from its platform, but the affair has raised concerns about the overall security of Facebook’s two billion monthly users.