The attorney general for the District of Columbia filed a lawsuit on Wednesday against Facebook for allowing Cambridge Analytica, a political consultancy, to gain access to the names, "likes" and other personal data about tens of millions of the social site's users without their permission.
The lawsuit filed by Karl Racine, confirmed Wednesday by two people familiar with the matter but not authorised to speak on record, marks the first major effort by regulators in the United States to penalise the tech giant for its entanglement with the firm. It could presage even tougher fines and other punishments still to come for Facebook as additional state and federal investigations continue.
Facebook did not immediately respond to requests.
The lawsuit comes as Facebook continues to face criticism around the world for mismanaging its users' personal information. On Friday, for example, the company admitted that some users' photos may have been improperly accessed by third-party apps.
On Tuesday, new details emerged about Facebook's extensive data-sharing arrangements with corporate partners including Amazon and Spotify. The report from The New York Times quickly triggered another round of calls from Capitol Hill for the tech giant to be penalised.