"We made significant progress in bridging the gaps," Obama said in a joint, written statement with House Speaker Nancy Pelosi and Senate Majority Leader Harry Reid. It was a reference to the significant differences in the versions of the House and Senate bills, legislation designed to expand coverage to millions and rein in long-term health care costs.

Pushed by Obama, senior Democratic lawmakers plunged into talks at the White House in a hurry-up bid for an overdue agreement. The unusually long meeting — it began at midmorning and was still going at sunset — underscored the urgency they and Obama felt about completing legislation on which they have staked so much.

The White House said the leaders covered all aspects of the legislation but it released no details about where the progress had been achieved or when the laborious process would end.

"Prospects of reaching agreement between the Senate and the House are better than they were 24 hours ago. We're getting close," House Majority Leader Steny Hoyer, D-Md., said after the daylong talks finally ended.

The negotiation sessions were expected to roll onward in the days ahead.

The House and Senate have passed different versions of the measure, which Obama wants to expand health coverage to millions who lack it, end insurance company practices such as denying coverage on the basis of pre-existing medical conditions and slow the rate of growth of medical costs overall.

Hoyer and others said the day's talks ranged widely over numerous areas of disagreement between the House and Senate. A key point was Obama's demand for a tax on high-cost insurance plans, a proposal designed to slow the inexorable rise in health care costs. House Democrats oppose the idea. So, too, does organized labor, and some union leaders were also at the White House during the day, although it was not clear whether they met with lawmakers.

The president's personal commitment in time was extraordinary.

Officials said he ducked in and out of the meeting with top Senate and House Democrats in the Cabinet Room throughout the day while also juggling his role in leading the U.S. response to Tuesday's devastating earthquake in Haiti.

Lawmakers shed their cell phones and Blackberries, standard procedure for a meeting in the room they occupied.

Numerous congressional aides were stationed in the Roosevelt Room down the hall, summoned to the negotiating table as the talks turned to their areas of expertise.

The House and Senate passed the bills with just one Republican vote and the GOP was not invited to the White House talks.

The proposed tax on insurance plans aside, the two sides worked for middle ground on the overall cost of the legislation and the size and extent of subsidies that would go to lower-income Americans who need help in paying for insurance.

The subsidies in the House bill are more generous than in the Senate measure, and it appeared lawmakers were in search of additional money.