A British lawmaker accused Facebook on Sunday of misleading officials by downplaying the risk of users' data being shared without their consent, after a former employee of data firm Cambridge Analytica says his company harvested information from 50 million Facebook users.

Conservative legislator Damian Collins, who heads the British Parliament's media committee, said he would ask Facebook chief Mark Zuckerberg or another Facebook executive to appear before his panel, which is investigating disinformation and "fake news."

Collins said Facebook has "consistently understated" the risk of data leaks and gave misleading answers to the committee.

"Someone has to take responsibility for this," he said. "It's time for Mark Zuckerberg to stop hiding behind his Facebook page."

Collins also accused the head of the U.K.-based data firm Cambridge Analytica, Alexander Nix, of lying. Nix told the committee last month that his firm had not received data from a researcher accused of obtaining millions of Facebook users' personal information.

Facebook suspended Cambridge Analytica, which is best known for working on President Donald Trump's 2016 campaign, on Friday over allegations it retained improperly obtained user data after claiming it had deleted the information.

Former Cambridge Analytica employee Chris Wylie said that the company obtained information from 50 million Facebook users, using it to build psychological profiles so voters could be targeted with ads and stories.

Wylie told Britain's Channel 4 news that the company was able to amass a huge database very quickly from an app developed by an academic that vacuumed up data from Facebook users who agreed to fill out a survey, as well as their friends and contacts—a process of which most were unaware.

"Imagine I go and ask you: I say, 'Hey, if I give you a dollar, two dollars, could you fill up this survey for me, just do it on this app', and you say, 'Fine,'" He said. "I don't just capture what your responses are, I capture all of the information about you from Facebook. But also this app then crawls through your social network and captures all of that data also."

Wylie said that allowed the company to get roughly "50 million plus" Facebook records in several months and he criticized Facebook for facilitating the process.

"Why Facebook didn't make more inquiries when they started seeing that, you know, tens of millions of records were being pulled this way, I don't know," he said.

Lawmaker Collins said he would summon Nix to reappear before the Parliament committee.

"It seems clear that he has deliberately misled the committee and Parliament by giving false statements," Collins said.