Facebook said Sunday that this information is uploaded to secure servers and comes only from people who gave explicit consent to allow it. Officials say the data is not sold or shared with users' friends or outside apps.
The FTC's confirmation that it is investigating Facebook is the latest of the social media giant's problems after the New York Times and British newspaper the Observer reported that Cambridge Analytica had aimed to use Facebook user data in an attempt to sway voter opinions.
USA regulators and state attorneys general are increasing pressure on Facebook as they probe whether the company's data-collection practices have hurt the people who use its services.
The data also features lists of friend requests sent by the user that were declined by others, offering a detailed picture on interactions with others on the site.
Tom Pahl, acting director of the FTC's Bureau of Consumer Protection, said the US probe would include whether the company engaged in "unfair acts" that cause "substantial injury" to consumers.
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.
"We remain strongly committed to protecting people's information".
Facebook chief Mark Zuckerberg took out full-page ads in nine major British and United States newspapers on Sunday to apologise for a huge data privacy scandal. The FTC's probe is centered around whether or not Facebook is in violation of a prior agreement they had reached to protect consumers.
Last week, the attorneys general of MA and NY announced they were launching investigations into Facebook. The chairman, Damian Collins, said his panel has repeatedly asked Facebook how it uses data.
Although Zuckerberg talked about changes in 2014 that would have prevented this, Rotenberg said it should have been banned already under the 2011 consent decree.
"We have a responsibility to protect your information".
Fewer than half of Americans trust Facebook to obey USA privacy laws, according to a Reuters/Ipsos poll released on Sunday, while a survey published by Bild am Sonntag, Germany's largest-selling Sunday paper, found 60 percent of Germans fear that Facebook and other social networks are having a negative impact on democracy. "Our internal review of the situation continues and we look forward to responding".