WASHINGTON, Dec. 19 (Xinhua) -- The attorney general for the District of Columbia filed a lawsuit Wednesday against Facebook over a privacy violation scandal in which the social media giant allegedly gave political consultancy firm Cambridge Analytica access to personal data of millions of users without noticing them.

"Facebook failed to protect the privacy of its users and deceived them about who had access to their data and how it was used," D.C. Attorney General Karl Racine said in a statement. "Facebook put users at risk of manipulation by allowing companies like Cambridge Analytica and other third-party applications to collect personal data without users' permission."

The complaint alleged that in 2013, a Facebook app conducting personality quiz ultimately sold personal information it collected from the quiz takers and their Facebook friends to Cambridge Analytica, which used it to help presidential campaigns target voters based on their personal traits. Cambridge Analytica provided consulting service for U.S. President Donald Trump's 2016 election campaign team.

The statement said 852 Facebook users installed the app developed by Alexandr Kogan of the Global Science Research company, but the app also collected personal information of those users' Facebook friends, and altogether it compromised the privacy of "nearly half of all District residents," estimated at more than 340,000 people.

After the lawsuit was filed, Facebook said in a statement, "We're reviewing the complaint and look forward to continuing our discussions with attorneys general in DC and elsewhere."