A spokesman for the European Commission on Friday said social networking site Facebook had confirmed the data of up to 2.7 million people in the European Union might have been shared with data mining firm Cambridge Analytica.
Among those, Facebook said about 310,000 users from Germany could be affected.
Read more: Facebook's Cambridge Analytica data scandal: What you need to know
Facebook revealed the extent of the data breach in the EU in a letter on Thursday that responded to questions from EU Justice Commissioner Vera Jourova.
On Wednesday, Facebook admitted it had "improperly shared" the personal data of tens of millions more users than previously estimated, putting the new number at 87 million users — an increase of more than 30 million.
Cambridge Analytica used the information without users' consent, apparently to support the leave campaign in the Brexit referendum, as well as the 2016 election campaign of US President Donald Trump.
'Coordinated approach crucial'
EU spokesman Christian Wigand said there would be further conversations with Facebook regarding EU users affected by the data sharing, and that Jourova was to have a phone call with Facebook's Chief Operating Officer Sheryl Sandberg "early next week."
Read more: Opinion: While privacy concerns persist, Facebook also contributes to democracy
"We will study the letter in more detail, but it is already clear that this will need further follow-up discussions with Facebook," Wigand said.
He added that the European data protection authority has also put the issue on its agenda for next Tuesday.
"A strong, coordinated approach of the EU data protection authorities in the investigations is now crucial," Wigand continued.
Read more: Opinion: The one way to control Facebook — delete your account
Italy launches investigation
Italy's competition authority opened an unrelated investigation on Friday into Facebook for allegedly misleading practices after it was revealed that the social network had sold users' data without their consent.
Authority chairman Giovanni Pitruzzella told Sky News24 that the investigation would be focusing on Facebook's claims on its home page that it is a free service, despite not revealing that it makes money off users' data.
Read more: Facebook: 'The truth has been lost'
The investigation comes as Italian consumer advocacy group Codacons prepares a US class-action against Facebook on behalf of Italians who had their data breached by Cambridge Analytica.
Codacons said while only 57 Italians downloaded the Cambridge Analytica app, an estimated 214,000 Italians may be affected because the mined data extended to the users' friends.
A top Facebook privacy official is due to meet with the authority later in April.
law/ng (AP, dpa)