Facebook chief executive Mark Zuckerberg (Manu Fernandez/AP)

Congressional calls for Facebook to testify on Capitol Hill grew louder and more bipartisan Monday, as lawmakers demanded that the tech giant explain how a data analytics firm that worked for President Trump’s campaign obtained names, “likes” and other personal information on 50 million people.

The increasingly sharp and personal tenor of the requests — many of which sought an appearance by chief executive Mark Zuckerberg — raised the odds for a fresh round of potentially contentious hearings, following lawmakers’ intense questioning of Facebook and two other technology companies last fall.

“While Facebook has pledged to enforce its policies to protect people's information, questions remain as to whether those policies are sufficient and whether Congress should take action to protect people's private information,” wrote Sens. Amy Klobuchar (D-Minn.) and John Neely Kennedy (R-La.) in a joint letter to Sen. Charles E. Grassley (R-Iowa), chairman of the Senate Judiciary Committee.

In their note, which asked Grassley to convene a hearing, Klobuchar and Kennedy said the panel should invite Zuckerberg and also the top executives from Google and Twitter. Those companies also appeared in hearings in October and November.

Those previous hearings focused on Russian manipulation of social media platforms to potentially affect the 2016 presidential election, but lawmakers now are aiming to grill Facebook on an even more sensitive matter: how it handles the personal information of its 2.1 billion users.

“A hearing featuring testimony with CEOs would provide the Committee the opportunity to hear an update on the progress of these companies' voluntary measures to combat attempted foreign interference and what is being done to protect Americans’ data and limit abuse of the platforms, as well as to assess what measures should be taken before the next elections,” they added.

Grassley has not yet scheduled such a hearing, and a spokesman did not immediately respond to requests for comment.

Facebook has denied any wrongdoing and has declined to comment on whether Zuckerberg would agree to appear on Capitol Hill.

“We are in the process of conducting a comprehensive internal and external review as we work to determine the accuracy of the claims that the Facebook data in question still exists,” said Justin Osofsky, the vice president of global operations, in a statement. “That is where our focus lies as we remain committed to vigorously enforcing our policies to protect people’s information.”

Facebook's shares were trading down nearly 7 percent on Monday afternoon.

Facebook has weathered heavy criticism after a whistleblower revealed in news reports over the weekend that Cambridge Analytica, a data analysis firm that worked for Trump's campaign, may have accessed the personal information of 50 million Facebook users without their permission.

Before changing its policies in 2014 and 2015, Facebook allowed developers of apps to gain detailed information on people who downloaded apps as well as their online “friends,” including names, education, work histories, birthdays, likes, locations, photos, relationship statuses, and religious and political affiliations. Such information can be extremely valuable to political campaigns for tailoring messages, ads and fundraising pitches.

Cambridge Analytica gathered such information through a psychological testing app, called Thisis­yourdigitallife, which offered personality predictions and billed itself on Facebook as “a research app used by psychologists.” Facebook said 270,000 people downloaded the app. The New York Times and the Observer of London have reported that allowed the collection of data on 50 million “friends.”

Facebook banned the parent company of Cambridge Analytica and two other people affiliated with the company Friday. Facebook publicly rejected assertions it had been “breached,” while Cambridge Analytica has denied any wrongdoing and said it always operated within the bounds of Facebook’s terms of service.

Yet lawmakers on Capitol Hill — some already frustrated with Facebook and its privacy practices — were left seething.

Sen. Richard Blumenthal (D-Conn.) urged the Federal Trade Commission on Monday to investigate Facebook. The FTC already penalized the company in 2011 for misleading consumers about its privacy practices. The consent decree settling the agency's investigation established several conditions, including that people whose data is shared with outside companies get notice and explicitly approve the sharing, according to former federal officials wrote drafted the consent decree. Facebook's sharing of data with Cambridge Analytica may have violated that settlement, triggering the possibility of many millions of dollars in fines, these former officials have said.

Blumenthal tweeted, “FTC should immediately investigate and sanction apparent breach by Facebook of its 2011 agreement guaranteeing protection of consumer info — now a hollow promise.”

The FTC did not immediately comment for this article. Facebook has said that it did not violated the 2011 consent decree.

Another Democrat, Sen. Ron Wyden (Ore.), wrote Zuckerberg directly on Monday, asking whether there had been other examples in which third-party app developers collected or processed user data in violation of the site's rules. And he pressed the company to detail whether it had or would notify any of the 50 million whose personal information landed in the hands of Cambridge Analytica.

Wyden said the reports about Cambridge Analytica throw into question “not only the prudence and desirability of Facebook's business practices and the dangers of monetizing consumers' private information, but also [raise] serious concerns about the role Facebook played in facilitating and permitting the convert collection and misuse of consumer information.” He demanded answers by April 13.

A leading member of Parliament in Britain, meanwhile, has called on Zuckerberg and Cambridge Analytica to testify, as well. A top regulator with the European Union, who is visiting the United States this week, said she would further question Facebook on the reports, too.