As part of a probe ordered in the wake of the Cambridge Analytica data scandal involving 87 million users, a US judge has ordered Facebook to hand over data of thousands of apps that violated its user privacy.
Facebook admitted last year that it suspended "tens of thousands" of apps for possible privacy violations.
A Massachusetts judge rejected the social networking giant's attempts to withhold the key details from state investigators, The Washington Post said in a report on Friday.
"We are disappointed that the Massachusetts Attorney General and the Court didn't fully consider our arguments on well-established law. We are reviewing our options, including appeal," a Facebook spokesperson Andy Stone was quoted as saying in the report.
Maura Healey, the Democratic Attorney General of Massachusetts, said: "We are pleased that the Court ordered Facebook to tell our office which other app developers may have engaged in conduct like Cambridge Analytica."
The state of Massachusetts launched the probe last September after Facebook admitted that it had suspended "tens of thousands" of apps on its platform as a result of its review on privacy practices launched following the scandal involving Cambridge Analytica.
The review, launched in 2018, followed revelations that the political consultancy hijacked personal data on millions of Facebook users and included attorneys, external investigators, data scientists, engineers, policy specialists and others, according to a Facebook statement.
The Cambridge Analytica scandal resulted in a record-breaking, $5 billion fine for Facebook from the US Federal Trade Commission (FTC).
In November 2019, Facebook revealed that at least 100 app developers may have accessed Facebook users' data for months, confirming that at least 11 partners "accessed group members' information in the last 60 days".
The social networking giant found that the apps -- primarily social media management and video streaming apps -- retained access to group member information, like names and profile pictures in connection with group activity, from the Groups API (application programming interface).