New York — Fox News host Tucker Carlson has come under fire for charged comments he recently made on immigration. Now it's proving to be costly to his show.

"We have a moral obligation to admit the world's poor, they tell us, even if it makes our own country poorer and dirtier and more divided," Carlson said.

After he made the comments last Thursday, critics called for advertisers to pull their ads. But on Monday, Carlson said he won't back down.

"We're not intimidated. We plan to say what is true until the last day," he said.

So far, more than a dozen advertisers like Pacific Life and IHOP have requested their ads not air on Carlson's program. But some haven't, like Mitsubishi and Bayer.

Carlson maintains his comments were in response to seeing debris in Tijuana where the migrant caravan has made camp. His views on immigration and other issues have come under fire before, and left-wing protesters have demonstrated outside his home.

Fox News said in a statement: "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."

Experts who follow TV ad sales told CBS News more than a dozen advertisers pulling ads is a big deal. But they said if Fox is able to get others to fill those slots, financially, the show will go on.