Critics of Kevin O’Leary’s proposed Box Elder County data center are suing the celebrity investor for falsely claiming that they were “proxies” for the Chinese Communist Party.

O’Leary reiterated his accusations targeting the Utah-based Alliance For A Better Utah and Gabrielle Finlayson, founder of Elevate Utah, in numerous media appearances. After receiving a demand to retract the claims, according to the suit, O’Leary said he had no evidence to back up the accusations and apologized.

But the federal lawsuit filed Wednesday — which also names Fox News, where O’Leary appeared several times — says O’Leary’s allegations were defamatory and that Joshua Kanter, Alliance For A Better Utah, Finlayson and her company, Elevate Strategies, suffered “devastating reputational harm, significant economic losses, severe emotional distress, and ongoing threats to their physical safety.”

“No American should have to fear having their livelihood destroyed because a TV businessman falsely branded them a foreign agent on national television,” said Matthew Platkin, the attorney for the plaintiffs and the former attorney general of New Jersey.

“Our clients were exercising their right to express their opinions about the future of their community. Rather than respond to their concerns, Kevin O’Leary chose to launch a national smear campaign built on absurd falsehoods that Fox News repeatedly affirmed and amplified,” Platkin said. “This lawsuit seeks to ensure there is accountability when powerful people weaponize lies to silence critics.”

The plaintiffs are asking the court to award compensation for the damages they suffered, as well as court costs.

Jeffrey Neiman, O’Leary’s lawyer, said his client “clarified his remarks weeks ago” and invited the groups to meet and discuss the project.

“Offered dialogue, they chose the courtroom — because this was never about reputation,” Neiman said. “It is a cash grab.”

Neiman said O’Leary would defend himself “vigorously,” and could file a countersuit when it is appropriate.

The attorney added, “We look forward to discovery and uncovering the facts related to the misinformation campaign against the data center in Utah.

In a statement, Fox News said it “publicly corrected the record on every program where on-air guest Kevin O’Leary’s comments were made, all of which was extensively publicized.”

They added, “We will vigorously defend against this lawsuit.”

Amid a public backlash to the massive data center plan for Box Elder County, O’Leary went on the offensive, claiming, according to the lawsuit, it was “irrefutable fact,” based on information from his team of data scientists, that Finlayson, Kanter and their organizations were agents of the Chinese government, fueling the opposition to the center.

“If they’re not, I want them to be able to defend their names,” O’Leary said on Fox Business. “Come out, come out, wherever you are.”

During the furor over the proposed center, Senate President J. Stuart Adams — who chairs the Military Installation Development Authority, which initially approved the project — requested that O’Leary agree to shrink the size of the center from 40,000 acres to 10,000, terms O’Leary eventually agreed to accept. It remains unclear if that means it will use less electricity or water.

Adams, who had been in the Legislature for two decades, lost his bid for reelection, losing the Republican primary in June.

And after O’Leary walked back the remarks last month, state Sen. Todd Weiler apologized for sharing O’Leary’s claim that China funded opponents of the data center proposal, and said that he was “duped.”

Correction: 5 p.m. • The story has been updated to correct the spelling of Gabrielle Finlayson’s name.