(Adds further Warren Twitter comments, paragraphs 5-7)
By David Shepardson and Elizabeth Culliford
WASHINGTON, Oct 1 (Reuters) - Facebook Inc Chief Executive Officer Mark Zuckerberg told employees in July that the company would "go to the mat" to defeat Democratic candidate Elizabeth Warren's expected effort to break up the world's largest social media company if she were elected president, according to audio of two internal company meetings published by The Verge.
"If she (Warren) gets elected president, then I would bet that we will have a legal challenge and I would bet that we will win the legal challenge. And does that still suck for us? Yeah. I mean, I don't want to have a major lawsuit against our own government," he said, according to the leaked audio.
Warren, who in March called for breaking up Amazon.com Inc , Facebook Inc and Alphabet Inc, quickly issued a retort on Twitter.
"What would really 'suck' is if we don't fix a corrupt system that lets giant companies like Facebook engage in illegal anticompetitive practices, stomp on consumer privacy rights," Warren tweeted.
In a later series of tweets, Warren noted that Facebook has built more market dominance in recent years by acquiring potential competitors WhatsApp and Instagram.
"More than 85% of all social networking traffic goes through sites owned or operated by Facebook," she wrote. "They've got a lot of power—and face little competition or accountability.
"They’ve bulldozed competition, used our private information for profit, undermined our democracy, and tilted the playing field against everyone else."
In the audio, Zuckerberg said breaking up big tech companies would make election interference "more likely because now the companies can't coordinate and work together."
Zuckerberg also drew laughter by saying Facebook's investment on safety is bigger than Twitter's entire revenue.
Zuckerberg issued a statement on his Facebook page, linking to The Verge's transcript, though he said it was meant to be internal.
"You can check it out if you're interested in seeing an unfiltered version of what I'm thinking and telling employees" he wrote in the post.
The Federal Trade Commission (FTC) has an open antitrust investigation into Facebook, and a group of state attorneys general led by New York is also investigating.
Other Democratic presidential candidates have also criticized Facebook. Senator Bernie Sanders said he would look to split up Facebook, Google and Amazon, while Senator Kamala Harris said a break-up should "seriously" be considered.
Senator Amy Klobuchar, one of the lawmakers who introduced the Honest Ads Act that would force Facebook to disclose purchasers of ads on the platform, announced her campaign with a speech that criticized major tech companies.
Another senior Facebook executive told Reuters this month the company is confident it would defeat an effort to break it up.
With more than 2 billion monthly users, Facebook been under scrutiny from regulators around the world over data sharing practices. It has also come under fire for failing to prevent Russian interference in the 2016 U.S. presidential election.
U.S. President Donald Trump and other Republicans have criticized social media platforms for alleged bias against conservatives, which the platforms have denied.
Zuckerberg was on Capitol Hill last month for the first time since he testified before the U.S. Congress in April 2018. While in Washington he met with Trump and members of congress.
In the tape, he was asked about refusing requests to give public testimony before legislators around the world including the U.S. Senate.
"It just doesn't really make sense for me to go to hearings in every single country that wants to have me show up," he told employees.
Reporting by Elizabeth Culliford in London; Ayanti Bera and Amal S in Bengaluru; David Shepardson in Washington; Editing by Shounak Dasgupta, Sandra Maler, David Gregorio and Cynthia Osterman