The freshman New Yorker made the shocking claim during an Instagram broadcast on Monday night and then doubled down Tuesday morning on Twitter.
"This administration has established concentration camps on the southern border of the United States for immigrants, where they are being brutalized with dehumanizing conditions and dying," she tweeted.
"This is not hyperbole. It is the conclusion of expert analysis."
A few hours later, she followed up her original tweet with a message directed at Republicans criticizing her statements.
"And for the shrieking Republicans who don’t know the difference: concentration camps are not the same as death camps," she wrote. "Concentration camps are considered by experts as 'the mass detention of civilians without trial.' And that’s exactly what this administration is doing."
Shortly after the tweets were posted, Congresswoman Liz Cheney, R-Wyo., accused the New Yorker of disgracing herself by making the comparison.
"Please @AOC do us all a favor and spend just a few minutes learning some actual history. 6 million Jews were exterminated in the Holocaust. You demean their memory and disgrace yourself with comments like this," she wrote.
Not to be outdone, Ocasio-Cortez quickly returned serve at her Republican counterpart.
"Hey Rep. Cheney, since you’re so eager to 'educate me,' I’m curious: What do YOU call building mass camps of people being detained without a trial? How would you dress up DHS’s mass separation of thousands children at the border from their parents?" she tweeted.
Rep. Cheney then replied: "Happy to help educate you @AOC. You could start with the @yadvashem survivor testimonies. I also recommend Night by Elie Wiesel. Here’s an Amazon link to make it easy for you to purchase."
Earlier in the day, Ocasio-Cortez's comments were also criticized by vice president of the National Border Patrol Council, Art Del Cueto.
"It's disgusting to compare concentration camps to what the men and women are doing here protecting our country," Del Cueto said on "America's Newsroom."
"It is definitely a slap in the face to a lot of those people who had family members who actually went through concentration camps."