As Facebook deals with the aftermath of revelations the data of 50 million of its users was misused, both the European Commission (EC) and the US Federal Trade Commission (FTC) are demanding answers.

Less than two weeks ago, The New York Times and The Guardian reported Cambridge Analytica obtained information on users, which was used to target voters ahead of the 2016 US election.

The EC asked Facebook if EU citizens were impacted, while Tom Pahl, acting director of the FTC’s Bureau of Consumer Protection unit, said in a statement it is running a “non-public investigation” and “takes very seriously recent press reports raising substantial concerns about the privacy practices of Facebook.”

“The FTC is firmly and fully committed to using all of its tools to protect the privacy of consumers. Foremost among these tools is enforcement action against companies that fail to honour their privacy promises…or that engage in unfair acts that cause substantial injury to consumers in violation of the FTC Act,” he added.

Meanwhile, Reuters reported EU Justice Commissioner Vera Jourova wrote a letter to Facebook COO Sheryl Sandberg, asking: “Have any data of EU citizens been affected by the recent scandal? If this is the case, how do you intend to inform the authorities and users about it?”

Jourova’s letter also asked if stricter rules were needed for social media “like those that exist for traditional media”.

Facebook CEO Mark Zuckerberg, who last week lamented the “breach of trust”, turned down a request from British politicians to answer questions on how the social network collects and stores user data. In a letter, the company said two senior executives would testify, but not Zuckerberg.

Since the revelations, Facebook lost more than $100 billion in market value.