Fox News host Tucker Carlson is leaning into the controversy his show generated last week, when the conservative cable news host implied that immigration makes the U.S. “poorer and dirtier and more divided.”

On Monday, amid fallout from advertisers, Carlson was defiant.

“The enforcers scream ‘racist!’ on Twitter, until everybody gets intimidated and changes the subject to the Russia investigation or some other distraction,” Carlson said. “It’s a tactic, a well-worn one. Nobody thinks it’s real. And it won’t work with this show. We’re not intimidated. We plan to say what’s true until the last day. And the truth is, unregulated mass immigration has badly hurt this country’s natural landscape.”

Carlson’s comments could hurt the show’s bottom line. The Daily Beast reported Monday evening that at least four advertisers are backing away from the prime-time program.

Fox News said in a statement Tuesday afternoon:

“We cannot and will not allow voices like Tucker Carlson to be censored by agenda-driven intimidation efforts from the likes of Moveon.org, Media Matters and Sleeping Giants. Attempts were made last month to bully and terrorize Tucker and his family at their home. He is now once again being threatened via Twitter by far left activist groups with deeply political motives. While we do not advocate boycotts, these same groups never target other broadcasters and operate under a grossly hypocritical double standard given their intolerance to all opposing points of view.”

The network said “no revenue has been lost” as a result of the advertiser boycotts, and pointed out that a number of brands have stood by the program.

Watch Carlson’s Monday evening comments: