WASHINGTON — The House yesterday approved a plan to expand federal backing of mortgages in hopes of helping struggling homeowners avoid foreclosure.

Despite some White House objections, the Bush administration and House Democrats took conciliatory stances pointing toward resolving their differences.

The bill passed the House 348-72. It would allow the Federal Housing Administration, which insures mortgages for low- and middle-income borrowers, to back refinanced loans for tens of thousands of borrowers who are delinquent on payments because their mortgages are resetting to sharply higher rates from low initial "teaser" levels.

Brian Montgomery, the Housing and Urban Development assistant secretary who heads the FHA, said the legislation could enable more than 200,000 homeowners whose loans are excluded from federal backing to come under the agency's umbrella.

"This is a historic day for FHA," Montgomery said after the vote. He said the administration is concerned about specific provisions — notably much higher limits in the bill for mortgages that could be insured by the agency, as much as $729,750 in high-cost areas compared with the current $362,000.

However, Montgomery added, "I feel optimistic we'll work out these differences" as the legislation moves through Congress.

In the Senate, the Banking Committee is expected to vote today on a version of the legislation proposed by panel chairman Sen. Christopher Dodd, D-Conn., and its senior Republican, Sen. Richard Shelby of Alabama.

The House measure is Congress' first stand-alone bill passed in response to the mortgage-market tumult of the summer, which came amid a rising tide of defaults and foreclosures.

The Senate last week approved spending legislation that includes $200 million in aid to nonprofits and other groups that offer counseling and information to help homeowners avoid foreclosure.

"The American dream is in peril for many families in this country as foreclosures rise and dreams shatter," Rep. Betty Sutton, a Democrat from Ohio, a state particularly hard-hit by the default wave, declared in House debate before the vote.

Rep. Barney Frank, D-Mass., chairman of the House Financial Services Committee, said he wanted to whisk the new House measure to the Senate along with a bill to tighten government oversight of mortgage finance giants Fannie Mae and Freddie Mac. The administration has insisted such legislation was needed before restraints on the amounts of mortgage securities the two government-sponsored companies are allowed to buy and hold could be eased.

Frank said he was ready to be flexible in negotiations with the White House on the legislative proposals and that he believed their enactment was possible before Thanksgiving.

In debate, House Republicans sharply objected to a $300 million-a-year fund for grants for affordable rental housing and homeownership assistance for low-income families, which would be financed from FHA revenues — a plan also opposed by the administration. Rep. Ed Royce, R-Calif., called it "an experiment in socialism."

But Republicans mostly were swept along in the vote for the bill, whose overall thrust they endorsed in the face of the mortgage crisis.

The bad news deepened again yesterday. Research firm RealtyTrac Inc. said the number of foreclosure filings reported in the United States last month more than doubled compared with August 2006 and jumped 36 percent from July.

An estimated 2 million to 2.5 million adjustable-rate mortgages are scheduled to "reset" this year and next, jumping from low "teaser" rates for the first two or three years to much steeper rates that could cost borrowers their homes.