A U.S. consumer protection agency said Monday it has opened an investigation into Facebook for potentially failing to live up to its promises on privacy and possible violations of a consent decree.
The Federal Trade Commission confirmed news reports from last week that it had opened an inquiry over the harvesting of Facebook data on tens of millions users of the social network by the British consulting group Cambridge Analytica.
While the FTC normally refuses to comment on its probes, it took the unusual step of confirming a "non-public investigation" into Facebook.
"The FTC is firmly and fully committed to using all of its tools to protect the privacy of consumers," said acting consumer protection chief Tom Pahl.
"Foremost among these tools is enforcement action against companies that fail to honor their privacy promises, including to comply with Privacy Shield (the US-EU privacy accord), or that engage in unfair acts that cause substantial injury to consumers in violation of the FTC Act."
Pahl added that companies who have settled previous FTC actions "must also comply with FTC order provisions imposing privacy and data security requirements."
Facebook signed a consent decree with the consumer agency in 2011 settling charges that it deceived consumers by telling them they could keep their information on Facebook private, and then allowing it to be shared and made public.
Pahl said the agency "takes very seriously recent press reports raising substantial concerns about the privacy practices of Facebook."
Facebook shares skidded more than five percent Monday after the announcement, after losing some 14 percent last week.
The world's biggest social network is also facing calls on both sides of the Atlantic for more information on how its user data was leaked.
A public apology by Facebook chief executive Mark Zuckerberg has failed to quell outrage over the hijacking of personal data.
