Senate leaders from both parties are discussing backup options to avert a U.S. default by adding spending controls to a plan that would grant President Barack Obama unilateral power to raise the debt limit.

Obama told lawmakers they have until tomorrow to decide whether they can reach a deal to make significant cuts in the deficit or settle for another way to raise the $14.3 trillion debt ceiling before U.S. borrowing authority expires Aug. 2, two Democratic officials said.

The president and bipartisan congressional leaders met today at the White House after yesterday's negotiations ended on a tense note and Moody's Investors Service warned that the stalemate could jeopardize the nation's credit rating.