WASHINGTON - Locked in a deepening struggle with President Barack Obama, the Republican-controlled House approved legislation early Sunday imposing a one-year delay in key parts of the nation's health care law and repealing a tax on medical devices as the price for avoiding a partial government shutdown in a few days' time.

Even before the House voted, Senate Democrats pledged to reject the measure and the White House issued a statement vowing a veto in any event. Republicans are pursuing "a narrow ideological agenda ... and pushing the government towards shutdown," it said.

The Senate is not scheduled to meet until mid-afternoon on Monday, 10 hours before a shutdown would begin, and even some Republicans said privately they feared that Senate Majority Leader Harry Reid, D-Nev., held the advantage in the fast-approaching end game. If so, a House GOP rank and file that includes numerous tea party allies would soon have to choose between triggering the first partial shutdown in nearly two decades - or coming away empty-handed from their latest confrontation with Obama.

Undeterred, House Republicans pressed ahead with their latest attempt to squeeze a concession from the White House in exchange for letting the government open for business normally on Tuesday. "Obamacare is based on a limitless government, bureaucratic arrogance and a disregard of a will of the people," said Rep. Marlin Stutzman, R-Ind.

Another Republican, Rep. Darrell Issa of California, reacted angrily when asked whether he would eventually support a standalone spending bill if needed to prevent a shutdown. "How dare you presume a failure? How dare you? How dare you?" he said.

Apart from its impact on the health care law, the legislation that House Republicans decided to back would assure routine funding for government agencies through Dec. 15. Under House rules, the measure went to the Senate after lawmakers voted 248-174 to repeal the medical tax, then 231-192 for the one-year delay in Obamacare.

A companion measure headed for approval assures U.S. troops are paid in the event of a shutdown.

The government spending measure marked something of a reduction in demands by House Republicans, who passed legislation several days ago that would permanently strip the health care law of money while providing funding for the government.

It also contained significant concessions from a party that long has criticized the health care law for imposing numerous government mandates on industry, in some cases far exceeding what Republicans have been willing to support in the past. Acknowledging as much, Rep. Trent Franks, R-Ariz., said that as a conservative he had often found during Obama's presidency that his choice was "between something bad or (something) horrible."

GOP aides said that under the legislation headed toward a vote, most portions of the health law that already have gone into effect would remain unchanged. That includes requirements for insurance companies to guarantee coverage for pre-existing conditions and to require children to be covered on their parents' plans until age 26. It would not change a part of the law that reduces costs for seniors with high prescription drug expenses.

One exception would give insurers or others the right not to provide abortion coverage, based on religious or moral objections.

The measure would delay implementation of a requirement for all individuals to purchase coverage or face a penalty, and of a separate feature of the law that will create marketplaces where individuals can shop for coverage from private insurers.

By repealing the medical device tax, the GOP measure also would raise deficits - an irony for a party that won the House majority in 2010 by pledging to get the nation's finances under control.

The Senate rejected the most recent House-passed anti-shutdown bill on a party-line vote of 54-44 Friday, insisting on a straightforward continuation in government funding without health care-related add-ons.

That left the next step up to the House - with time to avert a partial shutdown growing ever shorter.

For a moment at least, the revised House proposal papered over a simmering dispute between Speaker John Boehner and the rest of the leadership, and tea party conservatives who have been more militant about abolishing the health law that all Republican lawmakers oppose.

It was unclear whether members of the rank and file had consulted with Texas Sen. Ted Cruz, who has become the face of the "Defund Obamacare" campaign that tea party organizations are promoting and using as a fundraising tool.

In debate on the House floor, Republicans adamantly rejected charges that they seek a government shutdown, and said their goal is to spare the nation from the effects of a law they said would cost jobs and reduce the quality of care. The law is an "attack and an assault on the free enterprise and the free economy," said Rep. Pete Sessions of Texas.

Democrats disagreed vociferously. "House Republicans are shutting down the government. They're doing it intentionally. They're doing it on purpose," said Rep. Donna Edwards of Maryland, as Republican lawmakers booed from their seats on the floor.

In the Senate, there was little doubt that Reid had the votes to block a one-year delay in the health care program widely known as "Obamacare." He said the same was true for the repeal of the medical device tax, even though 33 Democrats joined all Senate Republicans in supporting repeal on a nonbinding vote earlier in the year.

The 2.3 percent tax, which took effect in January, is imposed on items such as pacemakers and CT scan machines; eyeglasses, contact lenses, hearing aids and other items are exempt. Repealing it would cost the government an estimated $29 billion over the coming decade.

If lawmakers miss the approaching deadline, a wide range of federal programs would be affected, from the national parks to the Pentagon.

Some critical services such patrolling the borders, inspecting meat and controlling air traffic would continue. Social Security benefits would be sent and the Medicare and Medicaid health care programs for the elderly and poor would continue to pay doctors and hospitals.

The new health insurance exchanges would open Tuesday, a development that's lent urgency to the drive to use a normally routine stopgap spending bill to gut implementation of the law.