WASHINGTON — President Barack Obama's top domestic priority, remaking US health care, took another step closer to becoming reality Thursday as his top House allies unveiled sweeping compromise legislation.

"Today we are about to deliver on the promise of making affordable, quality health care available for all Americans, laying the foundation for a brighter future for generations to come," said Democratic House Speaker Nancy Pelosi.

With time running short before a self-imposed year-end deadline, the House of Representatives could vote as early as next week on the measure, which includes a government-backed insurance plan to compete with private firms.

Democrats estimated the measure would cost $894 billion over 10 years and expand health insurance to 36 million Americans, helping to extend coverage to 96 percent of the population of the world's richest nation.

Democrats in the US Senate have crafted their own version, and if the two chambers approve rival measures they must forge compromise legislation to send to Obama to sign into law, a process that could easily run into 2010.

"Today, we are one step further on a long, hard road: The road to bring quality, affordable health care to every one of our fellow citizens," said Democratic Majority Leader Steny Hoyer.

Pelosi and Hoyer spoke at a rally on the same US Capitol steps where Obama took the oath of office nine months ago vowing changes that would bring the US health care system more in line with other rich democracies.

The president hailed the House legislation as a "historic step forward" and cast the measure as a blow against private health insurers and for taming runaway US health care costs.

"We can't wait another year for health insurance reform," Obama said in a statement that acknowledged "there will [be] more steps and much spirited debate before a bill reaches my desk."

None of Obama's Republican foes in the House has yet voted in favor of the Democrats' health care proposals this year, and an internal Democratic party schism over how much of a role to give the government has complicated passage in both chambers.

Representative Eric Cantor, the number-two House Republican, has denounced the Democratic approach as a "trillion-dollar government takeover of health care."

Republicans and some swing-vote Democrats say they fear a larger government role will drive private insurers out of business and result in lower quality of care.

The proposed changes would be the most wide-ranging overhaul of the way the United States manages its health care since the 1965 creation of the government-funded Medicare program for the elderly.