Billionaire 2020 presidential contender Mike Bloomberg doesn’t think Sens. Elizabeth Warren (D-MA) and Bernie Sanders (I-VT) “know what they’re talking about” when it comes to breaking up big tech companies, Mercury News reported on Friday.

“Breaking things up just to be nasty is not an answer,” Bloomberg, former New York City mayor, told the Bay Area News Group. “You’ve got to have a good reason and how it would work, and I don’t hear that from anybody, the senator or anybody else.”

Last March, Warren announced that, if elected president, she would seek to dismantle tech giants like Facebook and Google, accusing the companies of illegally using their market power to drown out competition.

“Breaking things up just to be nasty is not an answer.”

After her announcement, other Democratic candidates were pressed by reporters to respond. Some, like Sen. Amy Klobuchar (D-MN), said that regulators more thoroughly should investigate acquisitions like Facebook’s purchase of Instagram. Others, primarily Sanders, agreed that tech giants like Facebook, Google, and Amazon should be dismantled.

But in comments provided to reporters, Bloomberg said of Warren and Sanders: “I don’t think they know what they’re talking about.” According to Mercury News, Bloomberg does support “more limited antitrust enforcement.” He also appears to be in favor of reviewing Section 230 of the Communications Decency Act, a foundational internet law that protects social media companies from being liable for the content posted by users on its platforms.

A spokesperson for the Sanders campaign told The Verge that it wasn’t “surprising that a billionaire running for president wants to protect the wealth of his billionaire friends.” The spokesperson continued, “Mr. Bloomberg clearly doesn’t doesn’t grasp the danger of a single company controlling what we see, hear, and read. When Sen. Sanders is in the White House he will break up tech giants that have too much control over our country—and end their corporate greed.”

The Warren campaign did not immediately respond to a request for comment.