Democratic presidential hopeful Sen. Bernie Sanders Sunday defended his proposal for Medicare-for-all. Above, Sanders speaks at the 'First in the South' Dinner, Jan. 16, 2016, in Charleston, South Carolina. Andrew Burton/Getty Images

Sen. Bernie Sanders, I-Vt., Sunday defended his Medicare-for-all healthcare reform proposal and pledged to release details on how he would fund such a program “very soon.” Sanders, appearing on CNN’s “State of the Union” ahead of Sunday night’s Democratic presidential debate also said he would release his medical records, saying, “Thank God I’m very healthy.”

The Democratic presidential hopeful has been a proponent of universal healthcare and introduced legislation nine times that would expand the Medicare program to cover all Americans. The program would be administered by the states.

The Hillary Clinton campaign has criticized his plan, saying leaving such a program to the states would leave millions of Americans without coverage.

“All Americans are entitled to healthcare,” Sanders said. “Her campaign should not be suggesting my campaign would leave millions of people without health insurance.” He said if Republican-controlled states refused to implement such a program, the federal government would step in.

Sanders conceded implementing universal healthcare would be a tough political fight, but he said he thinks “we can rally the American people around two principles: the right of all people to comprehensive healthcare [and that] we should not be paying more than everyone else.” He was especially hard on pharmaceutical companies, whom he accused of making massive profits while making drugs prohibitively expensive.

Sanders lamented the cost of healthcare in the U.S. and insisted Medicare-for-all would make coverage “much more cost-effective.” Asked when he would release details on paying for the program, he responded, “very shortly.”

On ABC’s “This Week,” Sanders said details on funding his proposal will come out before the Feb. 1 Iowa caucuses. “We will increase Medicare premiums. That is true. But we will do away with all private premiums,” he said.