SanDisk, Samsung, SodaStream and Pfizer Inc. joined the list of advertisers cutting ties with Tucker Carlson’s Fox News Channel program in the wake of the host’s recent charged comments about immigration, increasing pressure on the 21st Century Fox-owned cable outlet, which has grappled for months with offensive remarks from several of its guests and hosts.

Approximately 20 advertisers of various stripes and spending have requested their commercials not appear in the program, “Tucker Carlson Tonight,” in the wake of remarks Carlson made last week suggesting immigration made the United States “dirtier.” Carlson on Monday reiterated his feelings on the matter, noting he would not be threatened by people who wanted to block him from expressing his opinion. “It’s a tactic, a well-worn one. Nobody thinks it’s real. And it won’t work with this show,” he said of an advertiser boycott. “We’re not intimidated. We plan to try to say what’s true until the last day.”

Fox News has backed up its 8 p.m. host, suggesting that progressive groups are behind the advertiser pull-out. “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,” the company said in a statement Tuesday. “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.”

A spokesperson for the network said advertisers who pulled commercials from Carlson’s show continued to run spots on the network, which had not lost any advertising revenue.

“Don’t let Fox News distract, deflect, or deceive. This isn’t about Media Matters, Sleeping Giants, or activists,” Media Matters for America said in a statement. “No one forced Tucker Carlson’s odious bigotry and fixation on white genocide conspiracy theories. And that’s what advertisers are rejecting. Rightfully so, too.”

Meanwhile, GLAAD, the advocacy organization representing the LGBTQ community, said Carlson’s charged rhetoric was hurtful. ““There’s no mistaking it: Tucker Carlson’s words were ugly, inaccurate, and un-American, and advertisers did the right thing by ending support of him and his show,” said Sarah Kate Ellis, President and CEO of GLAAD, in a statement. “Current and future advertisers must also remember Carlson’s pattern of peddling misinformation about and frequent attacks on other marginalized communities, including LGBTQ Americans. Fox News should take action and other advertisers should stand with marginalized communities by ending support of this derogatory programming.”

The advertiser concerns are the latest to hit Fox News, which has in recent months had to wrestle with polarizing remarks made by its three primetime hosts, Carlson, Sean Hannity and Laura Ingraham. Many of the sponsors are placed under scrutiny by progressive activist groups, who use the hosts’ off-putting comments to galvanize support and increase pressure on primetime sponsors. Laura Ingraham has twice come under a microscope this year, once for suggesting detention facilities for children being taken from migrants entering the U.S. illegally were like “summer camps,” and also for remarks she made on social media about one of the survivors of the shooting tragedy in Parkland Florida.

Fox News is walking a tightrope. On the one hand, its primetime hosts bring in the network’s biggest audiences, and these viewers are eager to hear what Carlson, Hannity and Ingraham have to say. And yet, their comments make some portion of sponsors uneasy. IHOP, SmileDirectClub, Ancestry.com, Voya Financial and Pacific Life are among the other advertisers who have requested their commercials not appear in Carlson’s program.

Some other sponsors have issued statements indicated they will stay with their current schedules on Fox that include “Tucker Carlson Tonight.” Mitsubishi, Bayer, John Deere, AstraZeneca and Sanofi have all said they won’t make changes to the way their commercials appear on Fox News. “Advertising decisions made by Farmers should not be construed to be an endorsement of any kind as to a show’s content or the individuals appearing on the show,” Farmers Insurance said in a statement.

In June, Fox News CEO Suzanne Scott urged producers to be more mindful of “protecting the talent, protecting the brand,” a nod to some of the recent controversies generated by on-air comments from guests and others. In recent weeks, personnel including Fox Business Network’s Stuart Varney and “Fox & Friends” co-anchor Steve Doocy have taken pains to admonish guests who have made outrageous remarks. Doocy scolded musician Kid Rock in November, for example, after he referred to “The View” host Joy Behar with an epithet.