Mark Zuckerberg, Facebook Inc.’s (FB.O) chief executive officer, is expected to testify before the U.S. House Energy and Commerce Committee, according to a congressional official familiar with the plans.

Zuckerberg has been the subject of withering criticism from both Republican and Democratic members of Congress, as well as members of the U.K.’s Parliament, over signs that Facebook has failed to protect user privacy. Lawmakers briefed this week by Facebook staff complained that the aides sent to closed-door briefings couldn’t answer many of their questions.

While the congressional official said Zuckerberg may appear on April 12, a Facebook spokesman said the company couldn’t confirm that date. Zuckerberg has decided he’s willing to testify, but congressional schedules are in flux and nothing is officially decided, according to another person familiar with the matter.

Facebook is struggling to stave off a barrage of criticism that it hasn’t done enough to address revelations that Cambridge Analytica, which worked with Donald Trump’s presidential campaign, siphoned data from about 50 million Facebook users as it built an election-consulting company that boasted it could sway voters in contests all over the world.

The U.S. Federal Trade Commission took the unusual step this week of confirming it’s investigating Facebook’s privacy policies following the revelations about Cambridge Analytica’s use of its data.

The developments have prompted some people to delete their Facebook accounts and have heightened concern that the social network will lose advertisers and be subject to tighter regulation. It’s also fueled a 16 per cent decline in Facebook shares. Facebook fell 3.4 per cent to US$154.65 at 1:59 p.m. in New York.

The leaders of the House panel, which oversees internet issues, sent an invitation to Zuckerberg dated March 23, saying it wanted to hold a hearing to “examine the harvesting and sale of personal information from more than 50 million Facebook users, potentially without their notice or consent and in violation of Facebook policy.”

The committee’s Republican chairman, Greg Walden of Oregon, told Bloomberg Radio that Facebook officials who briefed his committee couldn’t answer all of the members’ questions.

Zuckerberg will be under pressure to appear before other congressional committees, including the Senate Judiciary and Commerce panels, whose members will want him as a star witness.