Critics of the company say that the device-integrated APIs are a violation of that control, however, allowing device makers a direct line into user data.
The letter questioning his answers to Congress comes after The New York Times reported Sunday that Facebook gave companies like Apple and Samsung access to data without users' consent.
The deals allowed Facebook to expand its reach and let device makers offer customers popular features of the social network, such as messaging, "like" buttons and address books.
Following the Cambridge Analytica scandal, Facebook promised its users they would have full control over their data, noting that it cut off third-party access to detailed friend information back in 2015.
But privacy advocates have fretted that users may not have been aware of the extent that data about them, or their friends, had been transferred in the process.
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The company has since terminated 22 partnerships with device makers, he added.Shares of Facebook were down 1.8% pre-market at 6:34 am in NY on Monday, following a similar trend in Europe where it was down 2.2% at the same time in Frankfurt.Facebook is retooling its approach amid a global consumer and regulatory backlash.
"What we have been trying to determine is whether Facebook has knowingly handed over user data elsewhere without explicit consent", Elisabeth Winkelmeier-Becker, one of the German lawmakers who questioned Facebook in April, told the paper. Some partners, the newspaper found, can get at intimate data including Facebook users' relationship status, religion, political leaning and upcoming events. As a result, the social network allowed companies access to the data of user's friends without their explicit consent, raising concerns about whether the social network breached a consent decree with the Federal Trade Commission from 2011.
The New York Times reports that this has been a long-term partnership with the companies over the last decade, in the social media platform's bid to gain dominance.
Facebook, however, maintains their position that they did nothing wrong. "These partners signed agreements that prevented people's Facebook information from being used for any other objective than to recreate Facebook-like experiences."Regulators and authorities in several countries have increased scrutiny of Facebook after it failed to protect the data of some 87 million users that was shared with now-defunct political data firm Cambridge Analytica. And we approved the Facebook experiences they built", said Facebook's product partnerships chief, Ime Archibong, in a blog post".
A Blackberry spokesman said the company "did not collect or mine" the data given by Facebook.
The opprobrium over Facebook's data privacy practices continues.