U.S. President Barack Obama hailed a Senate vote backing his massive health care reform bill as "a big victory for the American people," as the legislation appears headed for a final vote on Christmas Eve.

U.S. Senators voted overnight and into the early morning hours Monday to end debate on the bill.

If the bill is later reconciled with one passed by the House of Representatives, supporters say it will mean as many as 30 million uninsured Americans will finally receive health insurance -- a cornerstone of Obama's platform.

The final vote, which held tightly to party lines, was 60 to 40. All 58 Democrats and the Senate's two independents held together for the vote against unanimous Republican opposition.

The outcome had been assured after Senate Majority Leader Harry Reid personally negotiated compromises on big issues over the last several months, culminating in last-minute concessions over the weekend to win over the final holdouts: independent Joe Lieberman of Connecticut and conservative Democrat Ben Nelson of Nebraska.

The vote came shortly after 1 a.m. even as a blizzard whirled around Washington outside the Senate doors.

Later Monday, Obama said the vote will make a "tremendous difference for families, for seniors, for businesses and for the country as a whole."

Obama also lashed out at critics who claim the legislation will increase health care costs.

"For all those who are continually carping about how this is somehow a big spending government bill, this cuts our deficit by $132 billion the first 10 years, and by over a trillion in the second," Obama said. "That argument that opponents are making against this bill does not hold water."

Though two more procedural hurdles remain in the days ahead, the outcome of Christmas Eve's final vote now appears assured.

"We'll get this passed before Christmas and it will be one of the best Christmas presents this Congress has ever given the American people," said Democrat Sen. Tom Harkin.

Republicans conceded that they were now likely powerless to stop the bill but vowed to force the debate to continue as long as possible.

Final passage of the bill requires a simple majority.

The legislation would make health insurance mandatory for the first time for nearly everyone. It would also provide subsidies to help lower-income people buy insurance, and induce employers to provide it, with tax breaks for small businesses and penalties for larger ones.

Democrats said early Monday they felt as though they were on the brink of something truly historic.

"Health care in America ought to be a right, not a privilege," said Senator Christopher J. Dodd, Democrat of Connecticut.

"Since the time of Harry Truman, every Congress -- Republican and Democrat -- every president -- Democrat and Republican -- have at least thought about doing this. Some actually tried."

Bill still faces challenges

Republicans accused the Democrats of trying to rush through the complex 2,700-page bill, which will cost the economy US$871 billion over 10 years.

Most contentious among the bill's provisions are the complex array of taxes that will help pay for the new coverage. The bill would impose an increase in the payroll tax for individuals earning more than $200,000 and couples earning more than $250,000 and it also calls for major reductions in government spending, by slowing the growth of Medicare.

Adoption of the legislation is not a certainty. Reconciling the Senate bill with the bill adopted by the House last month will be difficult say most observers.

The House bill includes, most notably, a government-run health insurance plan, or public option, but the Senate bill dropped that provision. There is also stricter abortion language in the House bill, and an excise tax on high-value insurance plans, a plan embraced by the Senate but strongly opposed by many House Democrats.

But both bills would ban highly unpopular insurance practices such as denying people coverage based on pre-existing conditions. And young adults could retain coverage longer under their parents' insurance plans -- through age 25 in the Senate bill and through age 26 in the House version.

For many Democrats, the landmark vote summoned the memory of late Senator Edward M. Kennedy, a champion of universal health care for his entire career, who died in August.

Kennedy's widow, Victoria, sat in the front row of the spectator gallery to watch the vote. Several senators embraced her after the vote, with Sen. Charles E. Schumer of New York telling her: "Without him, it never would have happened."

With reports from The Associated Press