Facebook CEO Mark Zuckerberg testifies before Congress in April 2018.
"We are co-operating with investigators and take those probes seriously", a Facebook spokesperson told Business Insider.
The investigation is being overseen by United States attorney's office for the Eastern District of New York, and a grand jury has been convened, The NY Times reports that the focus of the investigation remains unclear for now.
The Times report emerged on the same day that Facebook saw widespread outages on its apps, including Facebook Messenger, Instagram and WhatsApp.
Those companies were among 150 with sharing deals that allowed them to see user contact information and other data.
But the social network has always said that it was misled by Cambridge Analytica, describing its role in the scandal as having been too lax in policing how other companies were using its service. "We've provided public testimony, answered questions and pledged that we will continue to do so".
Facebook did not immediately respond to a request for comment. The Department of Justice began probing the Silicon Valley company after a report showed Cambridge Analytica, a political consulting firm, used the platform to improperly obtained data on 87 million people to help President Donald Trump's campaign.
News of the controversial agreements emerged in June when the Times reported that Facebook had agreed to provide access to large amounts of user data to at least 60 different device makers - including companies like Apple, Microsoft, Samsung and BlackBerry.
Facebook is facing a slew of lawsuits and regulatory inquiries over its privacy practices, including ongoing investigations by the U.S. Federal Trade Commission, the Securities and Exchange Commission and two state agencies in NY.