WASHINGTON—The U.S. government is now constrained by its statutory debt limit, the Treasury Department said, prompting the start of “extraordinary measures” this Tuesday to keep America’s bills paid and putting pressure on Congress to lift the borrowing cap.

U.S. Treasury Secretary Janet Yellen said that the government will reach its statutory borrowing limit on Tuesday and begin employing "extraordinary measures" to keep from breaching the cap and risking a potential catastrophic default.

The nation will hit its roughly $36 trillion debt limit on Tuesday, when the Treasury Department will start taking extraordinary measures to allow the government to pay its bills, outgoing Treasury Secretary Janet Yellen said in a letter to congressional leaders on Friday.