The House on Tuesday approved a plan to expand federal backing of mortgages in hopes of helping struggling homeowners avoid foreclosure.

The bill, which passed the House, 348-72, 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.

The measure, which exceeds limits favored by the Bush administration, is Congress' first stand-alone bill in response to the mortgage-market tumult of the summer, which came amid a rising tide of defaults and foreclosures. The Senate last week passed spending legislation that includes $200 million to provide aid to nonprofits and other groups that offer counseling and information to help homeowners avoid foreclosure.

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

"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.