U.S. Senator Bernie Sanders is the latest Democratic presidential candidate to stake out a position on how to address college affordability and student debt, but he’s not offering a lot of details yet.

“Our plan forgives massive amounts student debt,” Sanders, a Vermont Independent, told CNN’s Dana Bash in an interview Sunday that touched on student debt cancellation.

His statement was a response to Bash’s question about how Sanders’ plans on student debt stack up against those of Senator Elizabeth Warren, a Massachusetts Democrat. Warren unveiled a plan in April that would cancel up to $50,000 in student debt for most of the nation’s 44 million borrowers.

Learn more about the 2020 candidates’ plans for student debt and college affordability.

Sanders declined to offer more specifics on his plan for student loan forgiveness during the CNN interview. When pressed by Bash, he said, “Our plan will cancel a substantial amount of student debt and in some ways probably go further than Senator Warren’s.” He added later, “I don’t have the plan in my pocket right now.”

Warren had said in a previous CNN interview that her proposal to wipe out $640 billion in student debt is “bigger” than Sanders’ and “goes further” than his.

Sanders’ representatives didn’t immediately respond to a request for more details on the plan. On his campaign website, Sanders says he will “substantially lower student debt.”

During the 2016 campaign, Sanders popularized the idea of tuition-free public college, a plan he’s carrying into the 2020 campaign. This time around most of the Democratic field supports some sort of free public college.

“Four years ago, when I talked about that idea, it was considered to be pretty radical,” Sanders said in the interview. “But I’m delighted to see that, all over this country, there is the understanding that education, higher education, is a right for all workers, for all Americans.”