Facebook acknowledged on Tuesday it was facing multiple inquiries from US and British regulators about the major Cambridge Analytica user data scandal.
The leading social network offered no details but its admission confirmed reports of a widening investigation into the misuse of private data by Facebook and its partners.
"We are cooperating with officials in the US, UK and beyond," a Facebook spokesman said in response to an AFP query.
"We've provided public testimony, answered questions, and pledged to continue our assistance as their work continues."
The Washington Post reported that the Securities and Exchange Commission, Federal Trade Commission and FBI as well as the Justice Department are looking into the massive breach of users' personal data and how the company handled it.
Facebook shares closed the shortened Nasdaq trading day down 2.35 per cent to $192.73, heading into an Independence Day holiday with investors mulling what effect the investigations may have on the California-based internet giant.
Facebook has admitted that up to 87 million users may have had their data hijacked by British consultancy Cambridge Analytica, which worked for US President Donald Trump during his 2016 campaign.