Sen. Bernie Sanders (I-VT) deviated from his general tendency to refrain from launching direct attacks against fellow candidates and took aim at Mayor Pete Buttigieg (D), who has criticized the socialist senator’s plan to provide tuition-free college to everyone, even billionaires.

Sanders joined Warren in criticizing Buttigieg on Tuesday in an Instagram post:

Sanders’ video features a clip of Buttigieg saying, “I just think rich people oughta be able to pay for their own tuition. I’m also concerned about a narrative emerging that ignores the fact that not everybody goes to college.”

“Buttigieg is wrong on both counts. Number one, of course, when we talk about making higher education, public colleges, and universities tuition-free, we mean not only college, but we mean trade schools as well,” Sanders said.

He continued:

There are millions of good jobs out there in construction and all kinds of areas where people are good at working with their hands. They don’t wanna go to college, and, of course, we are gonna make tuition free for those people, so what he’s saying is not accurate.

The video featured another clip of the South Bend mayor, who said, “I just don’t believe it makes sense to ask working-class families to subsidize even the children of billionaires.”

“I’m very glad that Mr. Buttigieg is worried that I have been too easy on upper-income people and the millionaires and billionaires that I’m gonna allow their kids to go to public colleges and universities,” Sanders said, adding, “Just by the way as they do go to public schools right now.”

He continued:

Trump’s kids can go to any public school, elementary school high school in the country tuition-free. But the point is, I happen to believe that when you talk about programs like Social Security, like health care, like higher education, they should be universal. The way you pay for them and the way I do it, not the way Buttigieg does it, is I do demand that at a time of massive income and wealth inequality, that the very rich will start paying their fair share of taxes, as will corporate America. You pay for it by raising revenue from the very rich, but then you say in a very simple way that any person who wants higher education, college, trade school, should be able to do it. You know right now that’s what we do with Social Security. It’s a popular program. It is a universal program.

Sanders’ critique follows an ongoing back and forth between Buttigieg and Sen. Elizabeth Warren (D-MA), both of whom have criticized each other over transparency. Warren has called out Buttigieg for holding closed-door fundraisers with wealthy bundlers, while Buttigieg has called on Warren to release her tax returns from the early 2000s and to be more forthcoming about her past legal work for corporate clients.

The Massachusetts senator has since disclosed that she made $1.9 million from private legal work, which includes work for corporate clients.

Alexandria Ocasio-Cortez, a Sanders supporter, dismissed Buttigieg’s general argument regarding “free” college, calling it a “GOP talking point used to dismantle public systems.”

“It’s sad to see a Dem candidate adopt it,” she tweeted:

This is a GOP talking point used to dismantle public systems, & it’s sad to see a Dem candidate adopt it. Let’s talk about why Republicans are wrong on this. Just like rich kids can attend public school, they should be able to attend tuition-free public college. Here’s why. https://t.co/pWprP0qrhG — Alexandria Ocasio-Cortez (@AOC) November 29, 2019

The freshman lawmaker also told a group at a town hall meeting over the weekend that she is “tired” of critics calling “free” college and Medicare for All handouts.

“I’m tired of this idea that Medicare for All and tuition-free public colleges are some handout from somebody else,” she told the crowd.

“Nobody else is giving us a damn thing. We build this on our own. We fund it. We establish it. We fight for it. We create it. And no one should be able to take it away from us as they have been. So that’s that on that,” she added: