WASHINGTON — Government-controlled mortgage finance companies Fannie Mae and Freddie Mac said yesterday they have immediately suspended all foreclosure sales involving occupied single-family and 2- to 4-unit properties through March 6, to give troubled borrowers more time to work with loan servicers to avoid losing their homes.

The move, which doesn't apply to vacant properties in foreclosure, is ahead of the Obama administration's roll-out of its national foreclosure prevention and loan modification program. The White House said President Obama next week will outline his much-anticipated plan to spend at least $50 billion to prevent foreclosures in a speech in Arizona, one of the states hit hardest 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 yesterday.

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.

Both Fannie Mae and Freddie Mac, which were seized by federal regulators last fall amid the market meltdown, had suspended foreclosure sales during the winter holidays and halted evictions from foreclosed properties until the end of this month.

Together, the companies own or guarantee about half of U.S. home loans.

Freddie Mac said it gives lenders servicing its mortgages broad authority to provide forbearance to borrowers who are not yet delinquent. It also allows for permanent rate reductions, mortgage term extensions, forbearance of principal or other modifications to borrowers who are already delinquent.

Meanwhile, several major banks are expanding their efforts to halt home foreclosures while the Obama administration develops its plan to help struggling homeowners.

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 to as high as 10 million in the coming years.

JPMorgan Chase & Co., Morgan Stanley and Bank of America Corp. said yesterday 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 it started in November.

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

Obama's announcement Wednesday 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."

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 yesterday, 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 the subsidies would be paid to companies that collect payments for mortgage investors up front, or whether they would stretch 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.