Facebook founder Mark Zuckerberg was on Tuesday summoned by a British parliamentary committee to explain how UK-based Cambridge Analytica managed to harvest the personal data of Facebook users.

Facebook is under fire after reports that Cambridge Analytica misused information from more than 50 million Facebook accounts to help Donald Trump win the 2016 presidential election. The social network has lost billions of dollars in market value since Monday.

In a letter addressed to Zuckerberg, Damian Collins, the chairman of the UK parliamentary media committee, said he has repeatedly asked Facebook how it uses data. He accused the social media giant of "misleading" the committee by "consistently understating" the risks surrounding data protection.

Read more: Inventor of internet: 'Regulate social media companies!'

"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," Collins said in the note. "Given your commitment at the start of the New Year to 'fixing' Facebook, I hope that this representative will be you."

The request to appear comes as British data protection authorities seek a warrant to search the London offices of Cambridge Analytica.

EU parliament invite for Zuckerberg

The Facebook chief has also been invited by the European Parliament to speak on the data misuse case.

"We've invited Mark Zuckerberg to the European Parliament," the body's president, Antonio Tajani, tweeted.

"Facebook needs to clarify before the representatives of 500 million Europeans that personal data is not being used to manipulate democracy."

US consumer watchdog 'probe' 

The social media network is also being probed by the US Federal Trade Commission (FTC), the regulatory agency in charge of consumer protection, over its use of personal data, Bloomberg News reported on Tuesday.

Facebook said on Tuesday it had been told by the FTC that it would receive a letter this week with questions about the data acquired by Cambridge Analytica, but it claimed to have had no indication of a formal investigation.

California Senator Dianne Feinstein, the top Democrat on Senate's Judiciary Committee, said on Tuesday Zuckerberg should testify in Congress about Facebook's use of its users' data. "Fifty million people lost their privacy," Feinstein told reporters.

"I think that we ought to have the head of Facebook, not their lawyer, not their number two, but their number one, come... state if they're really prepared to lead the industry to some controls that prevent all this from happening," she said.

Feinstein called on the chairman of the committee, Republican Senator Chuck Grassley, to hold hearings in the case. She also asked Grassley to seek testimony from Cambridge Analytica CEO Alexander Nix, who was suspended on Tuesday pending a probe.

Facebook will brief US Senate and House aides on Wednesday, Reuters news agency reported, citing congressional staff.

ap/kl (AP, AFP, Reuters)

Each evening at 1830 UTC, DW's editors send out a selection of the day's hard news and quality feature journalism. You can sign up to receive it directly here.