WASHINGTON - Running out of time, President Barack Obama softened his stand and signaled Wednesday he would back a short-term deal to prevent a disastrous financial default on Aug. 2, but only if a larger and still elusive deficit-cutting agreement was essentially in place. He called lawmakers to the White House in a scramble to find enough votes from both Republicans and his own party.

Obama met with the Democratic leaders of the House and Senate, and then separately with House Speaker John Boehner and his deputy, Majority Leader Eric Cantor, in hopes of cobbling together a big compromise. All signs pointed to a legislative fight that would play out to the end.

The president, pushing for a deal that would cut the nation's budget deficit across the next decade and extend the government's tapped-out borrowing power through the approaching election year, had threatened to veto any stopgap expansion of the nation's debt limit. He even challenged Cantor, R-Va., not to call his bluff about it in one confrontational moment last week.

Obama's now-calibrated position, offered by spokesman Jay Carney, reflected the reality: leaders are nearly out of time to head off unprecedented trouble. Carney said if a divided Congress and the White House can agree on a significant deal, Obama would accept a "very short-term extension" of the debt limit to let bigger legislation work its way through Congress.

Even a few days matters, given the stakes.

The government will exhaust its ability to borrow money and pay its bills come Aug. 2, an outcome that could sink the country back into recession, halt Social Security checks, send interest rates higher and erode the creditworthiness of the richest nation on earth.

The White House made clear Obama still opposes a short-term extension of the debt limit on the order of 30 days or more on the grounds that would just punt the problem. He reiterated that views in his meetings with lawmakers, a Democrat familiar with the talks said.

An aide to Boehner, R-Ohio, said the Republican leaders and the president will continue to talk, but no meeting had been scheduled.

Those familiar with the talks spoke on condition of anonymity to disclose details of the private discussions at the White House. All sides were keeping information tight as time slips by and negotiations grow sensitive.

The latest talks centered on what it will take to muster enough votes from both parties to muscle legislation through the House and Senate and raise the national debt limit. Congressional leaders say they want to prevent default, but they are far from agreed on how.

The divided-by-party nature of Obama's negotiations underscored his need to get a bottom line from Democrats in both chambers and the leaders of the Republican-run House.

His challenge with fellow Democrats is to persuade them to accept changes to the popular entitlement programs of Medicare and Social Security. With Republicans, Obama is slamming into opposition from conservatives who refuse to consider tax increases. Obama wants a mixed approach of higher taxes on the wealthy and spending cuts that share the pain.

"There is still time to do something significant," Carney said, urging compromise.

Realistically, though, the deadline for agreement is this week, not next week, given the time needed to craft, debate, pass and work out possible differences in legislation.

Senate Majority Leader Harry Reid, D-Nev., said Tuesday that the head of the Congressional Budget Office has told him it could take the scorekeeping agency two weeks to come up with an official cost estimate for even a relatively modest package of spending cuts.

Then there are the problems of moving the debt limit increase through the Senate, where the rules allow any single member to force delays.

Parliamentary experts say that if the Senate takes up the debt limit measure this Saturday, it could take more than a week, until Monday, Aug. 1, to pass the measure through the Senate, give the House time to consider it and make changes and then gain Senate approval one more time.

The Obama administration and Congress are also working on a backup plan to increase the debt limit if no big plan can be reached. It would allow Obama to raise the ceiling on his own unless overridden by Congress. Yet many House Republicans loathe that idea and have pledged to vote against it, raising doubts about how tenable even the fallback choice is.

That plan is the result of work by Reid and the Republican leader of the Senate, Mitch McConnell of Kentucky.

Obama is trying to seize on momentum from a proposal from a bipartisan "Gang of Six" senators that would cut the deficit by almost $4 trillion but lacks many specifics.

Obama met for less than an hour with Reid; Dick Durbin of Illinois, the No. 2 Democrat in the Senate and a member of the Gang of Six; House Democratic leader Nancy Pelosi of California and Rep. Steny Hoyer of Maryland, the No. 2 Democrat in the House.

A House Democratic aide familiar with the meeting said House Democrats stand with Obama on his push for a big bargain but without hurting seniors through cuts to Social Security, Medicare and Medicaid.

Obama's meeting with Boehner and Cantor ran roughly 90 minutes.

The plan by the Gang of Six is probably far too complicated and contentious to win passage before the Aug. 2 deadline. But the plan's authors hope it could serve as a template for a "grand bargain" later in the year that could erase perhaps $4 trillion from the deficit over the coming decade.

Even among Democrats, Rep. Chris Van Hollen, senior Democrat on the House Budget Committee, said lawmakers had too few details about the Gang of Six plan.

Pelosi, the top Democrat in the House, reacted positively Wednesday to the new plan, saying it "has some good principles in it."

However, Republican Rep. Howard "Buck" McKeon of California, chairman of the Armed Services Committee, blasted the plan in a missive to his panel members, saying it would cut the Pentagon much too deeply and would unfairly curb military health and retirement benefits.

The Gang of Six framework promises almost $4 trillion in deficit cuts, including an immediate 10-year, $500 billion down payment that would come as Congress sets caps on the agency budgets it passes each year.

It also requires an additional $500 billion in cost curbs on federal health care programs, cuts to federal employee pensions, curbs in the growth of military health care and retirement costs and modest cuts to farm subsidies.

Associated Press writers Andrew Taylor, David Espo, Erica Werner, Jim Kuhnhenn and Julie Pace contributed to this report.