Facebook chief Mark Zuckerberg broke his silence Wednesday on the data scandal rocking the social media giant, admitting mistakes that led to a "breach of trust" with its two billion users, and vowing to step up.
In his first public comments on the uproar over the harvesting of data on 50 million users by a British firm linked to Donald Trump's 2016 campaign, Zuckerberg told Facebook users the firm had "a responsibility to protect your data."
"If we can't then we don't deserve to serve you," he wrote on his Facebook page.
"I've been working to understand exactly what happened and how to make sure this doesn't happen again."
Zuckerberg's comments come after several days in which Facebook shares were pummeled and calls for investigations were launched on both sides of the Atlantic.
Writing on his Facebook page, Zuckerberg said "the most important actions to prevent this from happening again today we have already taken years ago."
"But we also made mistakes, there's more to do, and we need to step up and do it."
It has emerged that British consulting firm Cambridge Analytica obtained data on millions of people from an app developed by researcher Aleksandr Kogan, that was downloaded by thousands of Facebook users but also scooped up information from their friends.
"This was a breach of trust between Kogan, Cambridge Analytica and Facebook," Zuckerberg wrote.
"But it was also a breach of trust between Facebook and the people who share their data with us and expect us to protect it."
"We need to fix that."
Zuckerberg said some changes were made by Facebook in 2014 that addressed "abusive apps," and that "these actions would prevent any app like (the one linked to Cambridge Analytica) from being able to access so much data today."
While the transfer of such data is no longer allowed under Facebook rules, Zuckerberg vowed additional measures "to secure our platform."
Those will include an investigation of apps that had access to large amounts of information before the rules were changed, more restrictions on developers' data access and a requirement that developers obtain approval and sign a contract in order to ask anyone for access to their posts or other private data.
He said Facebook would launch a tool "to make sure you understand which apps you've allowed to access your data" which will be featured prominently.
"I started Facebook, and at the end of the day I'm responsible for what happens on our platform," Zuckerberg wrote.
"I'm serious about doing what it takes to protect our community... We will learn from this experience to secure our platform further and make our community safer for everyone going forward."