Facebook chief executive Mark Zuckerberg Mark Elliot ZuckerbergHillicon Valley: Trump's ban on TikTok, WeChat in spotlight | NASA targeted by foreign hackers | Instagram accused of spying in lawsuit The Hill's Morning Report - Sponsored by The Air Line Pilots Association - Trump contradicts CDC director on vaccine, masks Hillicon Valley: DOJ indicts Chinese, Malaysian hackers accused of targeting over 100 organizations | GOP senators raise concerns over Oracle-TikTok deal | QAnon awareness jumps in new poll MORE on Wednesday broke his silence on the controversy over his company's dealings with Cambridge Analytica.

Zuckerberg in a Facebook post acknowledged that Facebook had “made mistakes.”

“We have a responsibility to protect your data, and if we can't then we don't deserve to serve you. I've been working to understand exactly what happened and how to make sure this doesn't happen again,” Zuckerberg wrote.

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Zuckerberg said Facebook is “working with regulators” that are examining the issue, likely a reference to the Federal Trade Commission (FTC) and officials in the United Kingdom.

Before Wednesday, Zuckerberg had not commented publicly on reports that Cambridge Analytica — a data firm tied to Stephen Bannon that worked for President Trump Donald John TrumpBiden leads Trump by 36 points nationally among Latinos: poll Trump dismisses climate change role in fires, says Newsom needs to manage forest better Jimmy Kimmel hits Trump for rallies while hosting Emmy Awards MORE's campaign — obtained Facebook information on more than 50 million users in the United States.

The data was provided by a researcher who created an app called thisisyourdigitallife, where an estimated 270,000 people willingly handed over personal information. The researcher then tapped into the friend networks of those users, creating the large data set given to Cambridge Analytica.

Facebook said the researcher, Aleksandr Kogan, and Cambridge Analytica had certified to the company that the data had been deleted in 2015, but then did not do so.

In response, Facebook suspended Cambridge Analytica from its platform and opened an internal investigation.

"I started Facebook, and at the end of the day I'm responsible for what happens on our platform," Zuckerberg wrote.

"While this specific issue involving Cambridge Analytica should no longer happen with new apps today, that doesn't change what happened in the past. We will learn from this experience to secure our platform further and make our community safer for everyone going forward."

Cambridge Analytica has denied any wrongdoing.

In an post accompanying Zuckerberg's, Facebook Chief Operating Officer Sheryl Sandberg said the breach was was a “major violation of peoples' trust.”

Zuckerberg said his company would take new steps to prevent other actors from using its platform in the way that Cambridge Analytica did, including investigating apps with similar access to user data, restricting developers' data access and being more transparent with data collection.

Moving forward, the company said it will ban developers that do not comply with audits on what Facebook user data they have, strip developers of access to data they have on users who haven’t used their apps in three months and introduce an easily accessible tool to let users figure out what data apps are acquiring from them.

Zuckerberg said Facebook had taken steps since 2014 to reduce the amount of data that thirty-party developers could acquire on Facebook users but said that “there's more to do, and we need to step up and do it.”

Critics of Facebook, including a bevy of lawmakers on Capitol Hill, have said Cambridge Analytica’s use of the data is an example of the company not prioritizing the safety and security of its users.

Detractors have drawn a direct line from the controversy to Facebook failing to stop Russian attempts to use the platform in influencing the U.S. political process around the time of the 2016 election.

A growing number of Washington, D.C., legislators have called for Zuckerberg himself to testify before Congress, something he has never before done.

"You need to come to Congress and testify to this under oath," Sen. Ed Markey Edward (Ed) John MarkeySchumer: 'Nothing is off the table' if GOP moves forward with Ginsburg replacement Democrats see fundraising spike following Ginsburg death Democratic senator calls for eliminating filibuster, expanding Supreme Court if GOP fills vacancy MORE (D-Mass.) said in response to Zuckerberg's Facebook post.

Facebook is set to meet with congressional offices this week in an attempt to conduct damage control.

- This story was updated at 4:35.