Et tu, roommate?

Chris Hughes, who helped launch Facebook with Mark Zuckerberg in a Harvard dorm room 15 years ago, on Thursday called for the company to be broken up, spurring fresh calls from US lawmakers to tighten regulation.

In a blistering op-ed piece published in the New York Times, Hughes claimed that the 34-year-old billionaire CEO has power that is “unprecedented and un-American” and that the social network should be “separated into multiple companies.”

Hughes — who left Facebook 12 years ago to pursue various projects including an unsuccessful, four-year stint as owner, publisher and editor-in-chief of The New Republic — says that Zuckerberg’s influence is “staggering,” and has grown “far beyond that of anyone else in the private sector or in government.”

“Mark is a good, kind person. But I’m angry that his focus on growth led him to sacrifice security and civility for clicks,” wrote 35-year-old Hughes, whose net worth is estimated at $430 million.

After Hughes’ piece got published, US Sen. Elizabeth Warren — who has repeatedly called for the breakup of Facebook and other Silicon Valley giants — took to Twitter to express her support.

“Today’s big tech companies have too much power—over our economy, our society, & our democracy,” Warren wrote. “They’ve bulldozed competition, used our private info for profit, hurt small businesses & stifled innovation. It’s time to #BreakUpBigTech.”

Rep. Ro Khanna, a Democrat from California, said Hughes was right in his assessment that Facebook’s acquisitions of WhatsApp and Instagram should never have been approved.

Democratic Senator Richard Blumenthal agreed, telling CNBC that the Department of Justice needs to look into “appropriate antitrust remedies” surrounding the acquisitions.

In response to Hughes’ column, Facebook VP Nick Clegg said in a statement that the company welcomes accountability.

But you don’t enforce accountability by calling for the break up of a successful American company,” Clegg said. “Accountability of tech companies can only be achieved through the painstaking introduction of new rules for the internet.”

Hughes, who published a book about inequality last year, is married to Sean Eldridge, who in 2014 made an unsuccessful bid for a Congressional seat in upstate New York.

The tech tycoon claimed in his Thursday piece that Facebook’s board is more of “an advisory committee than an overseer” due to Zuckerberg’s 60-percent voting share in the company, which gives him almost complete control of Facebook, Instagram and Whatsapp, which billions of people use daily.

“I’m worried that Mark has surrounded himself with a team that reinforces his beliefs instead of challenging them,” Hughes warned.

Citing America’s tradition of breaking up monopolies like Standard Oil and AT&T, Hughes says that the government must bring Zuckerberg to heel and “check the domination of Facebook.”

“The American government needs to do two things,” Hughes wrote, “break up Facebook’s monopoly and regulate the company to make it more accountable to the American people.”

In addition to the Federal Trade Commission, which reportedly is preparing to slap Facebook with a fine as high as $5 billion for its privacy lapses, Hughes called for a new government agency designed specifically to regulate tech companies, with a mandate to protect consumer privacy — an area where Facebook has been battered by scandal in the past year.

“If we do not take action, Facebook’s monopoly will become even more entrenched,” Hughes warned. “With much of the world’s personal communications in hand, it can mine that data for patterns and trends, giving it an advantage over competitors for decades to come.”