Facebook is under pressure on both sides of the Atlantic to explain how a data analytics firm was able to mine private information from tens of millions of users.
"This is a major breach that must be investigated. It’s clear these platforms can’t police themselves. I've called for more transparency & accountability for online political ads."US Democratic Senator
The social media giant has suspended Cambridge Analytica, which worked for Donald Trump's 2016 presidential campaign.
Damian Collins, Chair of the UK's powerful Digital, Culture, Media and Sport Committee said Facebook had "consistently understated" the risk of data leaks and needed to explain itself to parliament.
“Data has been taken from Facebook users without their consent, and was then processed by a third party and used to support their campaigns. Facebook knew about this, and the involvement of Cambridge Analytica with it, and deliberately avoided answering straight questions from the Committee about it," he said.
Meanwhile US Senators called for CEO Mark Zuckerberg to testify before Congress, saying the platform could no longer be trusted to police itself. Adam Schiff, the lead Democratic member of the House Intelligence Committee said the company should be "thoroughly investigated".
Christopher Wylie, a former employee of Cambridge Analytica, told the US's Channel 4 News that the company had harvested information from more than 50 million Facebook users, and used it to target voters with political messages.
Facebook, meanwhile, says Cambridge Analytica violated its terms of service by retaining improperly obtained user data, despite claiming to have deleted it.