Facebook will brief US Senate and House aides on Wednesday, congressional staff said on Tuesday amid growing pressure on the social media company to answer questions over the use of its users' data.

A House Energy and Commerce Committee spokeswoman confirmed the briefing, as did a Senate aide.

The briefing comes amid some calls from lawmakers for Facebook CEO Mark Zuckerberg to appear before Congress.

Also, the head of data-mining firm Cambridge Analytica has been suspended, while government authorities are bearing down on the London-based firm over allegations it stole data from 50 million users to manipulate elections.

Cambridge's board of directors suspended CEO Alexander Nix pending an investigation after Nix boasted of various unsavory services to an undercover reporter with Britain's Channel 4 News.

Channel 4 broadcast clips Tuesday that also show Nix saying his data-mining firm played a major role in securing US President Donald Trump's victory in the 2016 election.

Nix said the firm handled "all the data, all the analytics, all the targeting" and said Cambridge used emails with a "self-destruct timer" to make its role more difficult to trace.

"There's no evidence, there's no paper trail, there's nothing," he said.

Cambridge Analytica was created around 2013, initially with a focus on US elections, with $15 million in backing from billionaire Republican donor Robert Mercer and its name chosen by future Trump White House adviser Steve Bannon, The New York Times reported. The company, which the Times said was staffed mostly by British workers then, assisted US Senator Ted Cruz's presidential campaign before helping Trump's.

Cambridge has denied wrongdoing, and Trump's campaign has said it didn't use Cambridge's data.

Senator Dianne Feinstein of California, the top Democrat on the Senate Judiciary Committee, called Facebook's latest privacy scandal a "danger signal".

She wants Zuckerberg's assurances that Facebook is prepared to take the lead on security measures that protect people's privacy - or Congress may step in.

Chris Wylie, who once worked for Cambridge Analytica, was quoted as saying the company used the data to build psychological profiles so voters could be targeted with ads.

Wylie has agreed to be interviewed by Democrats on the House Intelligence Committee.

In footage released Monday, Nix said the company could "send some girls" around to a rival candidate's house, suggesting that girls from Ukraine are beautiful and effective.

He also said the company could "offer a large amount of money" to a rival candidate and have the whole exchange recorded so it could be posted on the internet to show that the candidate was corrupt.

Also on Tuesday, a dozen consumer-advocacy organizations pressed the US Federal Trade Commission to investigate whether the release of data violated an agreement Facebook signed with the FTC in 2011.

Facebook shares fell as much as 5.2 percent to $175.41 Monday. The stock dropped another 2.6 percent Tuesday to close at $168.15.

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