(CNN) — Supporters of the Senate immigration bill’s path to citizenship are blasting comments Iowa Rep. Steve King made last week where he said that for every young undocumented immigrant who is a school valedictorian, 100 more are “hauling 75 pounds of marijuana across the desert.”

King made the comments in an interview Thursday with conservative news organization Newsmax. They were in response to criticism from anti-tax advocate Grover Norquist, himself a supporter of the Senate immigration overhaul.

The controversial comments focused specifically on so-called DREAMers, advocates for a path to citizenship for young undocumented immigrants, especially those with strong school records, who were brought to the United States by their parents. King acknowledged that there are undocumented immigrants for whom he has sympathy, with strong connections to the community and exemplary school performance.

“But they aren’t all valedictorians, they weren’t all brought by their parents,” King said.

“For everyone who’s a valedictorian there’s another 100 out there that, they weigh 130 pounds and they’ve got calves the size of cantaloupes because they’re hauling 75 pounds of marijuana across the desert. Those people would be legalized with the same act.”

Senior White House advisor Dan Pfeiffer went after King’s comments in a Tweet Tuesday afternoon. “Every member of the GOP should condemn Rep King for comparing the Dreamers to drug mules, they represent what is great about this country,” he said.

Earlier in the Newsmax interview, King lashed out at voices who have called him anti-immigrant. “There isn’t anyone that can fairly characterize me as anti-immigrant,” the Republican said.

“They’re conflating the terms anti-illegal immigrant and anti-immigrant.”

Even before the drug-running comments surfaced, the six-term Congressman has been defending himself against accusations of racism against immigrants. In an interview Sunday with Univision, he disputed allegations that he compared immigrants to dogs at a 2012 event in Iowa.

King has been critical of the path to citizenship in the Senate-passed immigration bill, calling it amnesty. That bipartisan bill passed the Senate by a 68-32 vote in June but has faced uncertain prospects in the Republican-controlled House.

House Republicans have vowed not to take up the Senate bill, instead preferring their own version with stronger border control provisions and without a pathway to citizenship for the 11 million undocumented immigrants estimated to be living in the United States.

It was King who proposed legislation passed by the House of Representatives in June that moved to end an Obama Administration policy deferring deportation for some young undocumented immigrants.