Washington - Congressional negotiators moved closer Tuesday toward a bipartisan deal that would extend a payroll tax holiday, unemployment benefits and Medicare payment rates for doctors, while finding more than $50 billion in cuts to reduce the package's effect on the federal deficit.

While President Barack Obama and congressional leaders publicly jousted over the negotiations, senior Democrats and Republicans worked behind the scenes toward a compromise that would extend the tax and unemployment benefits through the year. A deal also would mean that doctors would not see a drop in rates paid by Medicare, according to senior aides in both parties.

Aides stressed that final details are still being ironed out - including which cuts would be used to finance the unemployment and Medicare provision - but they were optimistic that a broad deal could come together and be approved by the end of the week. House Speaker John A. Boehner, R-Ohio, and his leadership team plan to map out their position to rank-and-file Republicans at a closed-door huddle Tuesday night.

In remarks at the Eisenhower Executive Office Building on Tuesday morning, Obama called it "good news" that House Republicans have agreed to a compromise on the tax holiday by allowing that piece of the package to be approved without offsetting spending cuts, a concession from their previous position.

But, he cautioned, "you can't take anything for granted here in Washington until my signature is actually on it," and he encouraged Americans to lobby their representatives in Congress to approve the measure "without drama, without delay."

The major breakthrough in negotiations on the broader package came over the weekend when the lead Republican negotiator, Michigan Rep. David Camp, informed his Democratic counterpart, Montana Sen. Max Baucus, that Republican leaders said they would agree to extend the tax holiday through the end of the year without requiring Democrats to offset the cost. Payroll withholdings, normally 6.2 percent, were lowered to 4.2 percent at the beginning of 2011 after the Obama White House negotiated a compromise tax plan with congressional Republicans.

The tax holiday, which is set to expire at the end of this month, saves the average worker more than $80 a month. Budget officials estimated that an additional 10-month extension would cost the Treasury about $100 billion.

Without the need to offset the extension, the Camp-Baucus talks had to result in only a little more than $50 billion in offsets to finance the unemployment benefits and the Medicare provision. The task became much easier as the numerous budget showdowns of 2011 produced hundreds of billions of dollars in spending cuts intended for much broader deals that never came to fruition, thus giving Baucus and Camp a menu of options from which to find the savings.

Republicans have demanded about $20 billion in savings from the Medicare program to finance the move to stabilize doctor rates, while Democrats have preferred to use savings from troop drawdowns in Iraq and Afghanistan. On unemployment benefits, which will cost about $30 billion, Democrats have been resisting GOP efforts to include a freeze on pay for federal workers or increased contributions to pension plans.

In addition, the two sides have been haggling over the maximum length of unemployment benefits, with the most recent Obama budget proposal setting the limit at 79 months and the previous Democratic proposal coming in at 93 months. Republicans want something less than Obama's latest offer.

Early Tuesday afternoon, after hedging her position a day before, House Minority Leader Nancy Pelosi, D-Calif., signaled support for the GOP offer to approve a payroll tax holiday as a stand-alone measure.

"We have long proposed bringing this tax cut to the floor without (offsetting cuts) and House Democrats will support it so that taxes are not raised on 160 million working Americans," she said in a statement.