mark zuckerberg facebook
© Stephen Lam / ReutersMark Zuckerberg
Mark Zuckerberg, head of the world's largest social media platform, has issued an apology for the scandal over Facebook's security. Zuckerberg chose a decidedly quaint medium through which to do so - the British newspaper.

The billionaire placed full-page ads in a number of Sunday publications in response to pressure from US and European governments following the leak of 50 million users' data to Cambridge Analytica. The UK political consulting firm is accused of using the information to influence the US presidential election. "We have a responsibility to protect your information. If we can't, we don't deserve it," the advert read. The Observer, the newspaper that has led the Cambridge Analytica revelations in recent days, also carried the ad.

Zuckerberg described the leak as a "breach of trust" and said Facebook was investigating other apps that had access to the data. "We expect there are others. And we find them, we will ban them and tell everyone affected," he said. The Facebook CEO has seen the value of his company drop as much as $50billion since the story broke last week.

Cambridge Analytica claims the data was obtained legally, and was deleted at Facebook's request. The offices of the consultancy firm were searched by Britain's data protection watchdog Friday night.

Zuckerberg's apology is seen by some as an attempt at damage limitation after the company saw advertisers deserting the platform in recent days. Mozilla and German financial institution Commerzbank have suspended their ads, while Tesla and SpaceX boss Elon Musk joined the #deletefacebook movement trending on Twitter by removing his company's Facebook pages.