A grand jury in New York has subpoenaed records from at least two smartphone makers that had entered into partnerships with the social media giant, said the report on Wednesday citing unnamed sources.
These two companies were among more than 150, including Amazon, Apple, Microsoft and Sony, that had cut sharing deals with Facebook, gaining broad access to the personal information of millions of its users.
These agreements allowed the companies to see users' friends, contact information and other data, sometimes without consent.
"We are cooperating with investigators and take those probes seriously," a Facebook spokesman was quoted as saying in a statement.
"We've provided public testimony, answered questions and pledged that we will continue to do so."