"It's a big deal. It is a real problem," Dimon told Maria Bartiromo on FOX Business Network's "Mornings with Maria" show, according to an excerpt of the interview that will air in full Monday.

"The bond market is going to have a tough time. I don't know if it's six months or six years," he said.

Dimon cautioned that once investors become aware of the impact of rising debt levels, interest rates would skyrocket and markets would be disrupted -- a dangerous scenario for the world's biggest economy.

"People vote with their feet," he stressed.

Investors "are going to be looking at the country, the rule of law, the inflation rates, the central bank policies," he said, warning that "if people decide that the US dollar isn't the place to be," financing US debt will become more expensive.

Historically, the United States has been able to rely on market appetite for low-interest US Treasury bonds to support its economy.

Yields briefly climbed last week, amid concerns about President Donald Trump's divisive budget plan.

The plan would among other things extend the gigantic tax breaks introduced during Trump's first term, spurring fears of a ballooning federal deficit.

In mid-May, for the first time ever, the United States lost its triple-A credit rating from Moody's.

When it announced the downgrade to Aa1, the ratings agency warned that it expects US federal deficits to widen dramatically over the next decade.

The White House's back-and-forth announcements of towering tariffs slapped on countries around the world are also creating considerable uncertainty and thus market volatility.

Dimon already warned in April of "considerable turbulence" facing the American economy, pointing to the impact of tariffs, trade wars, inflation and budget deficits.

US Treasury Secretary Scott Bessent on Sunday downplayed Dimon's predictions of a debt market crisis. 

"I've known Jamie a long time, and for his entire career he's made predictions like this," Bessent said during an interview on CBS.

"Fortunately, not all of them have come true."

Bessent acknowledged that he "was concerned about the level of debt."

But he said "the deficit this year is going to be lower than the deficit last year, and in two years, it will be lower again."

"We are going to bring the deficit down slowly," Bessent added, insisting that addressing the deficit was a "long process."

"The goal is to bring it down over the next four years, (and to) leave the country in great shape in 2028."