Breaking more than four days of silence, Facebook CEO Mark Zuckerberg admitted mistakes and outlined steps to protect user data in light of a privacy scandal involving a Trump-connected data-mining firm.

Zuckerberg said Wednesday that Facebook has a "responsibility" to protect its users' data and if it fails, "we don't deserve to serve you."

Zuckerberg and Facebook's No. 2 executive, Sheryl Sandberg, have been quiet since news broke Friday that Cambridge Analytica may have used data improperly obtained from roughly 50 million Facebook users to try to sway elections.

Facebook has already taken the most important steps to prevent such a situation from happening again, Zuckerberg said. For example, in 2014, it reduced access outside apps had to user data. However, some of the measures didn't take effect until a year later, allowing Cambridge to access the data in the intervening months.

Zuckerberg acknowledges that there is more the company needs to do.

In a Facebook post on Wednesday, Zuckerberg said it will ban developers who don't agree to an audit. An app's developer will no longer have access to data from people who haven't used that app in three months. Data will also be generally limited to user names, profile photos and email, unless the develop signs a contract with Facebook and gets user approval.

In addition to issuing his statement, Zuckerberg is slated to sit down with CNN's Laurie Segall for an interview to air on Anderson Cooper 360 at 9 p.m. ET Wednesday.

After two days of declines, shares of Facebook finished Wednesday with a gain. The stock was up $1.24, or 0.7 per cent, to finish at $169.39 US on Nasdaq. Last Friday, the stock was worth just over $185 US.

© The Associated Press, 2018
The Canadian Press