WASHINGTON (Reuters) - U.S. Treasury Secretary Janet Yellen said on Friday the nation could exhaust its ability to borrow this summer even if Treasury takes “extraordinary actions” to buy more time when the nation’s debt ceiling comes back into effect at the end of July. Yellen told reporters at the White House that while the Treasury could extend its ability to borrow by employing special measures if Congress did not act to raise the debt ceiling, those steps might buy only a “very limited” amount of time. “It is exceptionally challenging this time to try to figure out just how long those (extraordinary) measures are going to last in part because of higher and more volatile spending and revenue numbers associated with the state of the economy and the pandemic,” she said. “We are concerned that there are scenarios that give (a) very limited amount of additional time to use extraordinary measures,” Yellen added. “There are scenarios in which some time during the summer” room would run out even after special measures were employed, she said. Reporting by Steve Holland; Writing by Tim Ahmann; Editing by Andrea Ricci Our Standards: The Thomson Reuters Trust Principles.