Media reports published by the U.K. newspaper The Observer and The New York Times on the weekend outlined how 50 million Facebook profiles were mined for data by an app called "thisisyourdigitallife". The data was then transferred to Cambridge Analytica.
The London-based company worked on Facebook ads with President Donald Trump during his election campaign in 2016, where it provided details on American voters. But the data allegedly held by Cambridge Analytica was not used in the 2016 Trump presidential election campaign, the company claims.
So far, Zuckerberg has been silent on the issue but U.K. lawmakers want to hear from him. Damian Collins, a member of parliament, sent a letter to Zuckerberg Tuesday requesting that he appear in front of the Digital, Culture, Media and Sport Committee.
"The Committee has repeatedly asked Facebook about how companies acquire and hold on to user data from their site, and in particular about whether data had been taken without their consent. Your officials' answers have consistently understated this risk, and have been misleading to the Committee," the letter said.
Collins has asked Zuckerberg to respond by March 26.
Zuckerberg said at the start of the year that his personal challenge in 2018 was to fix Facebook's issues. But some investors have criticized his handling of the Cambridge Analytica issue. Collins said that now is the time for the Facebook CEO to step up.
"It is now time to hear from a senior Facebook executive with the sufficient authority to give an
accurate account of this catastrophic failure of process."
"There is a strong public interest test regarding user protection. Accordingly we are sure you will understand the need for a representative from right at the top of the organisation to address concerns. Given your commitment at the start of the New Year to 'fixing' Facebook, I hope that this representative will be you."
Zuckerberg is not obliged to appear in front of lawmakers. Facebook was not immediately available for comment. Its shares were down around 3 percent in early trade.
The "thisisyourdigitallife" app which collected Facebook data did so in a "legitimate way," the social media firm said. It was created by Cambridge academic Aleksandr Kogan and his company Global Science Research. The app required people to log in with their Facebook details, which is how it collected data. But it also harvested the data of users' friends.
Facebook shut the app down in 2015 because it said that it violated the terms of service by passing on the data to Cambridge Analytica.
Both Kogan and Cambridge Analytica have denied wrongdoing. Facebook has faced heavy criticism for not disclosing the issue earlier. Facebook said that all the parties that had received the data said it had been destroyed, although the company said it had received reports that not all the data was actually deleted.
On Monday, the U.K.'s data protection watchdog ordered Facebook to stand down when auditors hired by the social network visited the offices of Cambridge Analytica. The Information Commissioner's Office (ICO) told the tech giant, which was planning to investigate Cambridge Analytica's servers and systems, to withdraw from the latter's London premises.
Separately on Monday, British news station Channel 4 News broadcast an undercover sting which showed senior executives at Cambridge Analytica suggesting that entrapment techniques such as bribes and sex workers could be used to help a politician gain favor against a rival.
Cambridge Analytica said that Channel 4 "edited and scripted" the report to "grossly misrepresent" the conversations between the undercover reporters and the company's senior executives.