WASHINGTON — Senate Democrats edged away Wednesday from their goal of passing ambitious health care legislation by early August amid heightening partisan controversy over tax increases and a proposed new government role in providing insurance to consumers.

"I think the ultimate goal is to have a bill by the end of this year" that is signed into law by President Barack Obama, said Sen. Chuck Schumer, D-N.Y.

Separately, Republicans who met with Senate Majority Leader Harry Reid, D-Nev., said he expressed flexibility on the timetable, indicating that he was willing to allow more time before legislation is brought to the floor.

The evident slippage coincided with a formal announcement that the nation's hospitals had agreed to give up $155 billion in projected Medicare and Medicaid payments over the next decade, money that can help defray the cost of the legislation the administration wants.

"Folks, reform is coming. It is on track," Vice President Joe Biden said at the White House. He urged the Senate to enact legislation by the now-imperiled August goal.

Any failure to meet the goal would be a setback, but not necessarily a fatal one, for Obama's attempt to win legislation this year that slows the growth in health care costs and extends coverage to nearly 50 million Americans who now lack it.

In the House, Speaker Nancy Pelosi, D-Calif., has vowed to pass legislation by the end of July, and the leadership is in the midst of deciding which tax increases and spending cuts will be included in the bill to ensure that it does not add to the deficit.

In the Senate, it seemed clear that the drive to enact health care legislation was entering a new phase.

On Tuesday, the Democratic leadership made it clear that it viewed a proposed tax on certain health care benefits as unacceptable, at the same time it relayed word that it favors allowing the government to sell insurance to consumers.

Both those positions appeared to undercut much of the work Sen. Max Baucus, D-Mont., and the Finance Committee have been doing.

He has said for weeks that any legislation would call for a tax on certain health care benefits, and Republicans are strongly opposed to the idea of government intervention in the private insurance industry.