Senate leaders are working off-stage Saturday to reach a final-hours deal to avert a fiscal crisis, with no official proposals or votes expected until Sunday.
Senate Majority Leader Harry Reid, D-Nevada, has adjourned the chamber until Sunday so Democratic and Republican leaders can negotiate on a deal to present to the House.
House members will officially return to Capitol Hill on Sunday in expectation that the Senate will present them with a plan to stop tax increases that are scheduled to kick in next week.
Senate leaders from both sides of the aisle vowed late Friday to scramble over the weekend to produce a new bill, on the heels of a high-stakes White House meeting with President Obama that is seen as the last chance to come together before the tax-hike deadline.
Minority Leader Mitch McConnell said he hopes senators can come forward with a recommendation as early as Sunday. 
Several senior administration officials told Fox News late Friday night that McConnell, R-Ky., is showing strong signs that he will help seal a deal.
However, they acknowledges he will have a difficult time getting a deal passed in the Republican-controlled House, which  has so far rejected any plan that includes allowing tax rates to increase for higher-earning Americans.
Reid called the White House meeting Friday "very constructive." 
"We need to have everybody step back a bit," he said.
The pledge to work on a new bill is by no means a solution to the sweeping set of tax hikes set to hit Jan. 1, followed by steep spending cuts. Lawmakers still have to write the bill, and produce something that can pass both chambers. 
Obama, speaking from the White House briefing room late Friday, voiced a dose of doubt about the Senate leaders' final push for a deal. 
He said he's "modestly optimistic" but that if Reid and McConnell fail, the Senate should allow an up-or-down vote on a scaled-back proposal the president is pushing. 
"The hour for immediate action is here, it is now," Obama said. "We're now at the last minute, and the American people are not going to have any patience for a politically self-inflicted wound to our economy. ... We've got to get this done." 
Considering how late this effort is getting underway, lawmakers easily run the risk of missing the deadline and causing at least some uncertainty with Americans' tax bills starting next week. 
The developments late Friday, though, at least showed Reid and McConnell were beginning to work together. And it marked a decision by lawmakers that the Senate should make the first move -- for days, House Speaker John Boehner has insisted that the Senate act, but Reid has resisted and put the onus on the House. 
It's unclear what the new bill would entail. It appears the Senate wants to tweak the Obama plan, which would include an extension of current tax rates for most Americans -- but potentially adjust it so fewer earners see a tax hike, and add a provision dealing with a looming expansion of the estate tax. 
The debt ceiling, which Obama wants increased, would not be part of this bill. And a senior White House official admitted it is unclear how a looming set of spending cuts would be addressed.