The U.S. Congressional Budget Office has warned in a report issued Friday that there is a "significant risk" that the U.S. government will be unable to pay all of its debt obligations by June if the debt ceiling remains unraised.

"There is a significant risk that at some point in the first two weeks of June, the government will no longer be able to pay all of its obligations," wrote the federal agency.

The report also noted that the federal government's debt payments "will remain uncertain throughout May, even if the Treasury ultimately runs out of funds in early June."

Meanwhile, Treasury Secretary Janet Yellen reportedly said that the federal government will have to renege on some payments if Congress does not raise the debt limit. 

However, no plan on how the department would proceed has yet been presented to U.S. President Joe Biden.

"If Congress fails to do that, it really impairs our credit rating. We have to default on some obligation, whether it's Treasuries or payments to Social Security recipients," Yellen was quoted as saying in an interview with Bloomberg Television on Friday. 

"That's something America hasn't done since 1789. And we shouldn't start now. So we've not discussed what to do.”

Meanwhile, the U.S. Treasury Department said in a statement Friday that it had just $88 billion in what is known as "extraordinary measures" to help keep the government's bills paid as of May 10.

According to Bloomberg, that is lower than the $110 billion a week earlier, and meant that just over a quarter of the $333 billion of authorized measures were still available to keep the U.S. government from running out of borrowing room under the statutory debt limit.