Read Full Text: Facebook's Mark Zuckerberg Admits 'Breach of Trust' in Cambridge Analytica Scandal

Facebook CEO Mark Zuckerberg responded to the Cambridge Analytica data collection controversy Wednesday afternoon as Silicon Valley and concerned users continue to criticize the social media giant.

Zuckerberg acknowledged that the company had not lived up to its privacy expectations from users and addressed concerns over the data of friends being gleaned for information who downloaded Aleksandr Kogan's personality quiz app. The 33-year-old also walked users through the tumultuous past week since the data leak story was reported.

"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 Wednesday in a Facebook post, calling the incident a "breach of trust."

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

Zuckerberg took personal responsibility for the controversy and reiterated that he is serious about "protecting our community" and not abusing the trust of the social media network's more than 1 billion worldwide users.