Data held by Facebook on 87 million of its users may have been improperly shared with Cambridge Analytica, the company has said.
The number is 37 million higher than previous estimates in the information leak scandal.
On Wednesday, chief technology officer, Mike Schroepfer, shared the higher number as part of a corporate blog post about steps the company was taking to restrict the personal data available to third-party app developers.
In a rare conference call with journalists, Facebook boss Mark Zuckerberg has insisted he is still the right person to lead the company.
The tech giant’s founder and CEO admitted that it “didn’t do enough” to protect its users and promised that the company was now committed to taking more responsibility for keeping people’s data safe.
“We didn’t take a broad enough view of what our responsibility is. That was a huge mistake. It was my mistake,” he said at the start of the call.
Asked by a journalist if he still thought he was the best person to lead Facebook forward, Zuckerberg said “yes”, adding: “I think life is about learning from your mistakes and working out what you need to do to move forward.”
“When you’re building something like Facebook that is unprecedented in the world there are going to be things you mess up,” he added.
The world’s largest social media company has been hammered by investors and faces anger from users, advertisers and lawmakers after a series of scandals about fake news stories, election-meddling and privacy.
Last month, Facebook acknowledged that personal information about millions of users wrongly ended up in the hands of Cambridge Analytica, which worked on US President Donald Trump’s 2016 campaign.