Facebook co-founder Chris Hughes has called for the breakup of the social network, in an opinion piece in the New York Times.

"We are a nation with a tradition of reining in monopolies, no matter how well-intentioned the leaders of these companies may be. Mark's power is unprecedented and un-American," Hughes wrote on Thursday, referring to Mark Zuckerberg, his former business partner and college roommate and the current chief executive officer of Facebook.

Facebook owns the largest social network, with more than two billion users across the world. It also owns WhatsApp, Messenger and Instagram, each used by more than one billion people.

Hughes co-founded Facebook in 2004 at Harvard University with Zuckerberg and Dustin Moskovitz. He quit Facebook in 2007 and later said in a LinkedIn post that he made $500 million for his three years of work.

"It's been 15 years since I co-founded Facebook at Harvard, and I haven't worked at the company in a decade," said Hughes, who later was an online strategist for Barack Obama during the 2008 U.S. presidential campaign.

"But I feel a sense of anger and responsibility."

Later on Thursday, the company responded to the call from Hughes.

"Facebook accepts that with success comes accountability. But you don't enforce accountability by calling for the breakup of a successful American company," Facebook spokesman Nick Clegg said in a statement.

"Accountability of tech companies can only be achieved through the painstaking introduction of new rules for the internet. That is exactly what Mark Zuckerberg has called for."

'Mark is a good, kind person'

In one of a number of security and privacy scandals to hit the company, Facebook is accused of inappropriately sharing information belonging to 87 million users with the now-defunct British political consulting firm Cambridge Analytica.

Hughes said he last met with Zuckerberg in the summer of 2017, several months before the Cambridge Analytica scandal broke.

Facebook CEO Mark Zuckerberg testifies before a House energy and commerce committee hearing on Capitol Hill in Washington in 2018. (Andrew Harnik/Associated Press)

"Mark is a good, kind person, but I'm angry that his focus on growth led him to sacrifice security and civility for clicks," Hughes said.

"And I'm worried that Mark has surrounded himself with a team that reinforces his beliefs instead of challenging them."

Hughes is not alone in asking for the breakup of Facebook. Some lawmakers have called for federal privacy regulation and anti-trust action to dismantle big tech companies.

To promote competition in the tech sector, Democratic presidential candidate Sen. Elizabeth Warren vowed in March to break up Facebook, Amazon.com Inc. and Alphabet Inc.'s Google if she's elected U.S. president.

U.S. Sen. Richard Blumenthal, a Democrat, told CNBC on Thursday he thinks Facebook needs to be broken up, and that the U.S. Justice Department's antitrust division needs to begin an investigation.

Antitrust law makes such a proposal tough to execute because the government would have to take the company to court and win. It is rare to break up a company, but not unheard of, with Standard Oil and AT&T being the two biggest examples.