Senate finance committee member Olympia Snowe smiles Tuesday as she looks toward the Democratic side of the dais on Capitol Hill in Washington. (Charles Dharapak/Associated Press)

A major U.S. health-care reform bill took another step forward Tuesday as the influential Senate finance committee approved it by a vote of 14-9.

Republican Senator Olympia Snowe of Maine broke with her party to vote for the Democratic health-care bill, which will require all Americans to purchase medical insurance. She was the only Republican in Congress to do so.

"When history calls, history calls," she said as the committee debated the bill earlier in the day.

Hoping to garner Snowe's support, Democrats had spent months addressing her concerns about making health care affordable and finding the budget to pay for changes to the system.

Tuesday's vote brought U.S. President Barack Obama's plan to reform the country's health care system one big step closer to reality.

Obama thanked Snowe for having "the political courage and the seriousness of purpose that she's demonstrated throughout this process."

"This bill is not perfect, and we have a lot of difficult work ahead of us," Obama told reporters in the Rose Garden of the White House.

"There's still significant details and disagreements to be worked out over the next several weeks as the five separate bills from the Senate and the House are merged into one proposal.

"Now is not the time to pat ourselves on the back," he added.

The pivotal Senate finance panel approved the sweeping legislation, which would usher in a host of changes to the country's $2.5-trillion US medical system.

Much work remains ahead before a final bill arrives on Obama's desk, but action by the finance committee marked a significant advance, capping numerous delays as chairman Max Baucus held marathon negotiating sessions aimed at producing a bipartisan bill.

Insurance companies obliged to take all under new bill

Four other congressional committees acted before August to pass health legislation, so for months, all eyes have been on the finance committee, the last of the committees to approve the legislation.

With Democrats holding a 13-10 majority on the committee, the outcome of Tuesday's vote was not in doubt, but the final days before the long-anticipated vote were rocky.

The health insurance industry released a report contending that the legislation would cause hefty increases in premiums.

The drama threatened to overshadow the vote on the 10-year, $829-billion plan that Baucus has touted as the sensible solution to America's problems of high medical costs and too many uninsured.

The bill includes consumer protections such as limits on co-pays and deductibles and relies on federal subsidies to help lower-income families purchase coverage. Insurance companies would have to accept anyone wanting to buy their plan, and people could shop for insurance within new state marketplaces called exchanges.

Medicaid would be expanded, and though employers wouldn't be required to cover their workers, they'd have to pay a penalty for each employee who sought insurance with government subsidies.

The changes would be paid for by cuts to Medicare providers and new taxes on insurance companies and others.