Both sides are searching for a way to resolve a fiscal standoff that has shut down the federal government for eight days, with a critical date for raising the country's $16.7 trillion borrowing limit approaching in nine days.
House of Representatives Speaker John Boehner, a Republican, renewed his call for deficit-reduction talks with President Barack Obama, saying he was not "drawing any lines in the sand."
"It's time for us to sit down and have a conversation," Boehner told reporters after meeting with Republican House members. "There are no boundaries here. There's nothing on the table, there is nothing off the table."
(Read more: Boehner: No 'linesin the sand' on debt limit)
Republicans emerged from the House meeting saying they would insist that deficit-reduction talks with Obama as a condition for raising the federal debt limit.
The chief economist at the International Monetary Fund said on Tuesday a default by the United States would likely lead to a recession, dramatic cuts in government spending, and a "a lot of financial turmoil."
"I think what could be said is if there was a problem lifting the debt ceiling, it could well be that what is now a recovery would turn into a recession or even worse," IMF chief economist Olivier Blanchard said.