WASHINGTON - The Bush administration has hammered out an agreement to freeze interest rates on certain subprime mortgages for five years to combat an escalating number of home foreclosures, congressional aides said yesterday.

The aides, who spoke on condition of anonymity because the details have not been released, said the five-year moratorium was a compromise between desires by banking regulators for a time frame of up to seven years and mortgage-industry arguments that the freeze should last only one or two years.

Another person familiar with the matter said the rate freeze would apply to borrowers with loans made from Jan. 1, 2005, through July 30 of this year with rates that are scheduled to rise between Jan. 1, 2008, and July 31, 2010.

"Fixing the reset period is an important action, and it's good that everyone now seems to be pushing in the same direction," said Michael Barr, a professor at the University of Michigan Law School.

The administration said President Bush would speak about the agreement at the White House today, and the Treasury Department announced that Treasury Secretary Henry M. Paulson Jr. and Housing and Urban Development Secretary Alphonso Jackson would hold a joint news conference this afternoon with mortgage-industry officials.

Treasury also announced that there would be a technical briefing to explain more of the proposal's details. Paulson briefed House Republicans on the plan yesterday.

Paulson, who has been leading the effort to craft a plan, said on Monday that the program would only be available for owner-occupied homes - to ensure the break is not given to real estate speculators.

The plan emerged from talks among banking regulators, including Paulson, banks, mortgage investors and consumer groups. They are trying to address an expected avalanche of foreclosures as an estimated two million subprime mortgages adjust, or reset, from lower introductory rates to higher rates over the next 18 months.

In many cases, the higher rates would boost monthly payments as much as 30 percent.

The plan is aimed at homeowners who are making payments on time at lower introductory mortgage rates but cannot afford a higher adjusted rate.

This year through October, there were about 1.8 million foreclosure filings nationwide, compared with about 1.3 million in all of 2006, according to RealtyTrac Inc., of Irvine Calif. With home-loan defaults on payments still rising, the trend is expected to worsen next year.

The rescue plan is an about-face for Paulson, who until recently had insisted the mortgage crisis could be handled on a case-by-case basis.

Under the typical subprime loan - mortgages offered to borrowers with spotty credit histories - the rates for the first two years were 7 percent to 9 percent. But after two years, those rates were scheduled to reset to 9 percent to 11 percent.

That would add up to $350 to a typical $1,200 monthly payment, raising the risks of loan defaults by homeowners struggling with their current payments.

About 100,000 subprime loans will jump from their discounted initial rates every month for the next two years, brokerage firm UBS AG estimated.

The administration plan lets subprime borrowers who are living in their homes and are current on their payments avoid a reset for five years. The hope is that, by that time, the housing downturn will have stabilized, clearing out the glut of unsold homes and halting the steep slide in prices that is hitting many parts of the country.