(Photo: Xinhua)

WASHINGTON, Nov. 1 (Xinhua) -- US Senator Elizabeth Warren, a top-tier Democratic presidential contender, unveiled a plan on Friday to pay for her Medicare for All proposal.

Warren's proposal, which would cover health care and long-term care for everyone living in the United States, while eliminating private insurance, would cost 20.5 trillion US dollars in new federal spending over ten years, according to details published on her campaign website.

The Massachusetts Democrat said she doesn't need to raise taxes on the middle class "by one penny" to finance Medicare for all. Instead, she recommended new taxes on the rich, corporations and employers, as well as cuts to defense spending.

The plan marked a shift from Warren's progressive rival in the Democratic race, Senator Bernie Sanders of Vermont.

A co-sponsor of a 2017 Medicare for All expansion bill to cover all Americans, Sanders, who's running for president the second time on a progressive platform, has said tax hikes on the middle class will be necessary to help pay for Medicare for All.

Warren's plan came as the latest New York Times-Siena College poll released on Friday showed she is currently leading in Iowa, an early voting state, and is holding a slim lead over Sanders.

Former Vice President Joe Biden, who has led in most national polls, is falling to the fourth place behind Pete Buttigieg, mayor of South Bend, Indiana, ranked the third at 18 percent, according to the poll.

A spokesperson for the Biden Campaign called the Warren proposal "unrealistic."

"To accomplish this sleight of hand, her proposal dramatically understates its cost, overstates its savings, inflates the revenue, and pretends that an employer payroll tax increase is something else," the spokesperson said in a statement.

Four Democratic primary debates have been held so far in this election cycle, with health care being a hot topic.