The Anti-Defamation League on Monday strongly rebuked Rudy Giuliani, calling the Trump attorney’s assertion that liberal philanthropist George Soros is “hardly a Jew” a dog whistle to anti-Semites.

In an interview with New York correspondent Olivia Nuzzi, the former New York mayor—just back from another Ukrainian mission to dig up dirt on former Vice President Joe Biden—claimed that former U.S. Ambassador to Ukraine Marie Yovanovitch was “controlled” by Soros. “He put all four ambassadors there. And he’s employing the FBI agents,” Giuliani declared in remarks nearly identical to pro-Trump lawyer Joe diGenova that recently sparked backlash from Jewish organizations.

“Don’t tell me I’m anti-Semitic if I oppose him,” Giuliani later said in the booze-soaked interview. “Soros is hardly a Jew. I’m more of a Jew than Soros is.”

“I probably know more about—he doesn’t go to church, he doesn’t go to religion—synagogue. He doesn’t belong to a synagogue, he doesn’t support Israel, he’s an enemy of Israel,” he added. “He’s elected eight anarchist DA’s in the United States. He’s a horrible human being.”

Giuliani’s comments immediately set off a firestorm of criticism.

In a statement to The Daily Beast, ADL CEO Jonathan Greenblatt said: “Mr. Giuliani’s assertion that George Soros controls US Ambassadors, employs FBI agents and is ‘hardly a Jew’ is baffling and offensive. Let’s be crystal clear: Mr. Giuliani is not the arbiter of who is Jewish and who is not, or what is anti-Semitic and what is not.

“For decades, George Soros’ philanthropy has been used as fodder for outsized anti-Semitic conspiracy theories insisting there exists Jewish control and manipulation of countries and global events. Mr. Giuliani should apologize and retract his comments immediately, unless he seeks to dog whistle to hardcore anti-Semites and white supremacists who believe this garbage.”

Giuliani, meanwhile, apparently is standing by his comments. Asked by NBC News if his comments were made in jest, the ex-mayor texted back: “I'm more Jewish than half my friends.”