Facebook's Mark Zuckerberg broke his silence Wednesday on the Cambridge Analytica data scandal that's plagued the social media giant in recent days and slashed stock value.

"We have a responsibility to protect your data, and if we can't then we don't deserve to serve you," Zuckerberg said in a statement posted to his Facebook page.

The research firm is accused of improperly gaining access to the personal data of more than 50 million Facebook users. Facebook says it learned of the misuse in 2015 but failed to notify the public before last weekend, when a pair of reports by The Observer newspaper in the U.K. and The New York Times revealed how the personal information had changed hands.

Zuckerberg said Facebook would notify users whose data was included in the set allegedly received by Cambridge Analytica and would also:

— Investigate all apps with access to Facebook data and demand audits of any app with "suspicious activity"

— Restrict developers' data access even further to prevent other kinds of abuse

— Launch a tool at the top of the News Feed that will show users which apps have access to their data and allow them to revoke those apps' permissions

Facebook on Wednesday outlined six initiatives it will take to prevent a similar incident from occurring in the future.

Zuckerberg will also appear on CNN at 9 pm ET to address the matter.

"I've been working to understand exactly what happened and how to make sure this doesn't happen again," he said. "I started Facebook, and at the end of the day I'm responsible for what happens on our platform. I'm serious about doing what it takes to protect our community."

The founder and CEO had reportedly planned to wait until after the company's audit of the alleged mishandling of data before making any sort of comment. But Facebook's audit hit a roadblock earlier this week when U.K. lawmakers launched their own probe and instructed Facebook to back down.

Zuckerberg's comments follow days of tech insiders, lawmakers and even Facebook employees calling for input from Facebook's highest executive and COO Sheryl Sandberg on the company's latest privacy scandal.

"I deeply regret that we didn't do enough to deal with it," Sandberg said Wednesday in her own Facebook post. "You deserve to have your information protected — and we'll keep working to make sure you feel safe on Facebook. Your trust is at the core of our service. We know that and we will work to earn it."

Zuckerberg outlined a timeline of relevant events, starting in 2007 with the creation of the Facebook platform and ending on the weekend, when Facebook said it was banning Cambridge Analytica from the platform in light of the news reports.

Cambridge Analytica received the data from Cambridge University researcher Aleksandr Kogan, whose psychology quiz app collected data from nearly 300,000 Facebook users and their friends, Zuckerberg said.

Zuckerberg reiterated in his comments that the social media platform has changed its policies to prevent apps like Kogan's from collecting data on users' friends, without those friends' explicit permission.

"The good news is that the most important actions to prevent this from happening again today we have already taken years ago," Zuckerberg said. "But we also made mistakes, there's more to do, and we need to step up and do it."

Here's Zuckerberg's full statement: