When a software engineer employed by Facebook asked billionaire Mark Zuckerberg to comment on Democratic presidential candidate Sen. Bernie Sanders' position that billionaires should not exist, fellow employees began to laugh.

Facebook CEO and co-founder Zuckerberg also chuckled after a moment's pause. Those in attendance at Thursday's live-streamed town hall-style internal meeting began supportively to applaud.

"It's a good question ... All right," Zuckerberg said.

In the answer that followed, Zuckerberg – who, with a net worth of $67 billion, is listed by Forbes as the fourth wealthiest American – said he was sympathetic to Sanders' views on income inequality.

"I understand where he's coming from," he said, noting he couldn't put a threshold on how much wealth is too much.

"At some level, no one deserves to have that much money."

He went on to say he sees potential advantages to some Americans' ability to accumulate even "unreasonable" amounts of wealth, too.

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He cited his own philanthropic pledges as an example: Zuckerberg and wife Dr. Priscilla Chan have pledged to give away 99% of their Facebook shares in their lifetime.

Zuckerberg said that while critics might argue billionaires' charitable gifts would benefit the nation more as tax dollars, he says his philanthropy is funding scientific research projects that would likely be ignored by the government.

"I think the alternative would be the government chooses all of the funding for all of the stuff," he commented.

"Part of what makes progress happen is people taking different approaches to different things," he went on to say.

The exchange happened at a weekly "internal Q&A" that was publicly live-streamed on Zuckerberg's Facebook page. Usually the sessions are only for employees but a previous Q&A session made headlines this week when Zuckerberg was heard saying in leaked audio that he would "go to the mat" to fight efforts aimed at breaking up the social networking giant.

That sparked a response from another Democratic presidential hopeful: Sen. Elizabeth Warren, who defended her plan to break up big tech companies.

Zuckerberg was asked Thursday about Warren's plans and responded: "Let's try not to antagonize her further."

On Friday, Warren tweeted a video clip of the question and the start of Zuckerberg's response.

"If Facebook finds my scrutiny uncomfortable, here's what Mark Zuckerberg and his team could work on," Warren tweeted, listing protecting consumers' privacy, ensuring Facebook "isn’t undermining our election security" and ending "his company's illegal anticompetitive practices."

Contributing: Kelly Tyko, Jessica Guynn, Brett Molina