WASHINGTON (AP) — Several major banks are expanding their efforts to halt home foreclosures while the Obama administration develops its plan to help struggling homeowners.

The White House said President Barack Obama on Wednesday will outline his much-anticipated plan to spend at least $50 billion to prevent foreclosures in a speech in Arizona, one of the states hardest hit by the foreclosure crisis.

"It's not intended to be measured by one day's market scorekeeping, but instead to ensure that the 10,000 Americans each day that have their homes foreclosed on, and the millions more that are barely getting by, are protected," White House press secretary Robert Gibbs said Friday without providing other details.

Treasury Secretary Timothy Geithner announced a revised effort to stabilize the financial system on Monday. It contained outlines of a foreclosure-relief effort, but few details.

Though lenders have beefed up their efforts to aid borrowers over the past year, their action hasn't kept up with the worst housing recession in decades.

More than 2.3 million homeowners faced foreclosure proceedings last year, an 81 percent increase from 2007, and analysts say that number could soar as high as 10 million in the coming years, depending on the severity of the recession.

JPMorgan Chase & Co., Morgan Stanley and Bank of America Corp. said Friday they are halting foreclosures through March 6. And Citigroup Inc. said its halt will extend until the administration has completed the details of the loan modification program or March 12, whichever is earlier. New York-based Citi's action expands on a similar effort that it started in November.

The banks' pledges apply to owner-occupied homes, not those owned by investors.

Obama's announcement next week is expected to include details about how the administration plans to prod the mortgage industry to do a better job of modifying the terms of home loans so borrowers have lower monthly payments.

Testifying before House lawmakers this week, Geithner said the government would provide incentives to "try to induce economically sensible restructuring of mortgages," but offered no specifics. A Treasury spokeswoman declined further comment Friday.

A Democratic Senate aide said the plan is likely to include hefty payments designed to encourage the lending industry to lower mortgage rates or reduce the total principal amount owed by borrowers. The idea has become attractive to Obama officials, the aide said Friday, because it is expected to be far less expensive than having the government buy up loans out of mortgage-linked securities.

It was unclear whether those government subsidies would be paid to companies that collect payments for mortgage investors up front, or whether they would stretch out over several years.

Howard Glaser, a mortgage industry consultant who served in the Clinton administration, said if 2 million borrowers' payments were lowered by $500 a month, it would cost the government and lenders $6 billion each per year — assuming lenders match half the cost.

Unlike previous loan modification plans, borrowers would not have to be in default to qualify, according to people briefed on the plan.

Still, figuring out who would qualify would be a challenge, especially as foreclosures continue to soar. More than 274,000 U.S. households received at least one foreclosure-related notice last month, according to RealtyTrac Inc., an Irvine, Calif.-based foreclosure listing service.

Government-controlled mortgage finance companies Fannie Mae and Freddie Mac have developed systems to analyze millions of loans and determine which ones need to be modified. But to qualify for those programs, borrowers have to be at least three months behind on their home loans.

At the White House, Gibbs cautioned about the dangers of erroneous information leaking out about the foreclosure plan because he did want to see
"an unreasonable series of expectations based on leaks from God knows where."

Still, the administration is widely expected to back a push in Congress — but opposed by the mortgage industry — to let bankruptcy judges alter the terms of primary home loans. Earlier this week, Obama said it "makes no sense" that judges are not allowed to do so.

The hope is that, rather than being dragged into bankruptcy court, lenders would prefer to modify loans. The mortgage industry argues that this prohibition allows lenders to charge lower rates.

The top executives of Bank of America, and Citi announced their intention to halt foreclosures under questioning from House lawmakers on Wednesday.

Jamie Dimon, JPMorgan's chief executive, detailed his plans in a letter to Rep. Barney Frank, D-Mass., the chairman of the House Financial Services Committee, who released it on Friday.

"We stand ready to work with you to put the appropriate processes in place, including a national modification standard, to reduce the incidence of foreclosure and to encourage long-term, sustainable home mortgages," Dimon wrote.

Gibbs said he thought the banks' action was "consistent with what the president believes is at least part of something that would be likely seen in a housing policy that protects the American people."

Fannie Mae and Freddie Mac suspended foreclosure sales during the winter holidays and have halted evictions from foreclosed properties until next month. And earlier this week, John Reich, director of the Office of Thrift Supervision, urged the more than 800 thrift institutions nationwide to do the same.

Associated Press Writers Ben Feller, Christopher S. Rugaber and Madlen Read contributed to this report.