U.S. Treasury Secretary Janet Yellen said Sunday that she believes the country’s chances of paying all its bills by June 15 are "quite low" and warned that some bills will go unpaid if Congress fails to raise the debt ceiling.

Yellen made the remarks during an interview on NBC’s "Meet the Press," saying that June 1 remains the hard deadline for Congress to reach an agreement.

"And my assumption is that if the debt ceiling isn't raised, there will be hard choices to make about what bills go unpaid," Yellen said, stopping short of saying which specific bills would go unpaid.

President Biden’s administration and Republicans led by House Speaker Kevin McCarthy are at a standstill over raising the country's borrowing limit, now at $31 trillion, to keep paying the nation’s bills. 

Negotiations early Friday ended abruptly before the teams reconvened in the evening, only to quickly conclude for the night.

Republicans are demanding steep spending cuts opposed by Democrats, while Democrats insist that Republicans agree to tax hikes on the wealthy, in addition to spending cuts, to close the deficit.

With the June deadline approaching, Yellen said it is "not an acceptable situation" for the U.S. to be unable to pay its bills in any scenario.

"I would say we are focused on raising the debt ceiling and there will be hard choices if that doesn't occur," she said. "There can be no acceptable outcomes if the debt ceiling isn't raised, regardless of what decisions we make."

The Associated Press contributed to this report.