The breach of the debt ceiling officially starts the clock on how long Trump and Congress will have to act to avoid a financially catastrophic default.

Treasury secretary Janet Yellen, in one of her final major acts in office, warned Congress late Friday that the Treasury will need to begin "extraordinary measures" on Tuesday to avoid hitting the debt limit.

In one of her last acts as Treasury Secretary, Janet Yellen says her agency will start taking “extraordinary measures,” or special accounting maneuvers intended to prevent the nation from hitting the debt ceiling,