Facebook said Wednesday that the number of users whose data was swept up by Cambridge Analytica could be as high as 87 million, significantly more than the figure of 50 million that was widely reported at the outset of the data scandal more than two weeks ago.
The firm has worked with political groups all around the world - including US President Donald Trump's election campaign.
A spokesman for Facebook did not immediately respond to an email seeking comment.
The laws only apply to European Union member states, but many privacy advocates are calling for companies to extend the consumer protections globally. Years earlier, Cambridge Analytica improperly appeared to access the names, "likes" and other personal information from at least 30 million Facebook users, according to Christopher Wylie, a former employee turned whistleblower.
Among the proposed changes is an updated data policy, which goes into greater detail about the information Facebook gathers from the devices used to access it. Although Facebook says the changes aren't prompted by recent events, it's an opportune time.
Their call represented the first official request from a congressional oversight committee for Zuckerberg's appearance as lawmakers demanded that Facebook explain reports that Cambridge Analytica harvested the data of more than 50 million Facebook users. He's also scheduled for a conference call with reporters on Wednesday afternoon.
Facebook CEO Mark Zuckerberg has agreed to testify before the House Energy and Commerce Committee on April 11, the chairman and top Democrat on that committee announced Wednesday.
"This hearing will be an important opportunity to shed light on critical consumer data privacy issues and help all Americans better understand what happens to their personal information online", it said in a statement.
Facebook says the data of more than 620,000 Canadians was likely shared improperly with a political consulting company that is at the centre of an worldwide uproar over the use of social-media information for political purposes. Greg Walden and Frank Pallone say the hearing will focus on the Facebook's "use and protection of user data".