Democratic presidential candidate Elizabeth Warren said Sunday that she will soon release a plan detailing how to pay for "Medicare for All" after facing criticism from some of her 2020 rivals for declining to get into specifics about how her health care plan would be funded.

"What I see though is that we need to talk about the cost and I plan over the next few weeks to put out a plan that talks about, specifically, the cost of Medicare for All and specifically how we pay for it," the Massachusetts senator said during a campaign stop in Indianola, Iowa.

Warren has backed 2020 competitor Sen. Bernie Sanders' Medicare for All plan. She said Sunday that every Democratic candidate knows "the cheapest possible way to make sure that everyone gets the health care that they need is Medicare for All, and that's why I support Medicare for All."

"You know right now the cost estimates for Medicare for All vary by trillions and trillions of dollars and the different revenue streams for how to fund it, there are a lot of them," she said. "So, this is something I've been working on for months and months and it's got just a little more work until it's finished."

As Warren has reached a neck-and-neck point with former Vice President Joe Biden in the polls, the rest of the field has stepped up attacks on her, focusing in on how she would fund Medicare for All. She came under fire during the most recent Democratic primary debate when she refused to give a yes or no answer on whether the middle class would face a tax increase to pay for the plan, in addition to more broadly refusing to clearly spell out how the plan would be funded.

TJ Ducklo, a Biden campaign spokesman, said in a statement it was "mystifying that for someone who has put having a plan for everything at the center of her pitch to voters, Senator Warren has decided to release a health care plan only after enduring immense public pressure for refusing to do so."

Sanders has said the middle class would be subjected to a tax increase to fund the health care plan, but insisted Americans would pay less toward health care costs overall as a result of his plan being passed.