Revelations that Facebook lost control of 50 million user profiles has already angered lawmakers in the US and UK. Now, the US Federal Trade Commission is looking into it too.

The FTC is probing whether Facebook violated the terms of a 2011 consent decree, according to reports Tuesday from Bloomberg News and The Washington Post, citing people familiar with the matter. The decree required that Facebook users receive notification of and agree to Facebook sharing their data with outside firms.

"We remain strongly committed to protecting people's information," Facebook Deputy Chief Privacy Officer Rob Sherman said in a statement. "We appreciate the opportunity to answer questions the FTC may have."

Representatives from the FTC didn't immediately respond to CNET's request for comment.

The FTC probe represents the largest legal and political threat Facebook faces in reaction to the widening scandal over mishandled user data. According to New York Times and Guardian reports, a data mining firm called Cambridge Analytica improperly received information from more than 50 million user profiles through Aleksandr Kogan, a University of Cambridge lecturer who created an app that ostensibly offered personality predictions. Instead, it was apparently used to leak information about Facebook users, including their location and likes, and then did the same to their friends.

The scandal has been exacerbated by Facebook itself, which attempted to get ahead of the news by putting out a notice about the data leak Friday and then argued with reporters over the weekend about whether it should be labeled a "breach". The company argued, among other things, that it had been lied to by Cambridge Analytica and Kogan. As of Tuesday morning, neither CEO Mark Zuckerberg nor COO Sheryl Sandberg has publicly discussed the issue in official statements or in missives to Facebook's more than 2 billion monthly active users.

Meanwhile, pressure from lawmakers in the UK and US is ramping up. Representatives on both sides of the Atlantic have said they intend to question the social networking giant, and possibly Zuckerberg himself, over the scandal.

"Mark Zuckerberg needs to testify before the Senate Judiciary," Sen. Amy Klobuchar, a Minnesota Democrat, tweeted Saturday shortly after the scandal broke. "They need to take responsibility for what's going on."

First published March 20 at 8:39 a.m. PT.
Update at 9:28 a.m. PT: Adds background.

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