WASHINGTON — The Bush administration has hammered out an agreement with industry to freeze interest rates for certain subprime mortgages for five years in an effort to combat a soaring tide of foreclosures, congressional aides said today.

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

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

The administration said that President Bush will speak on the agreement at the White House tomorrow and the Treasury Department announced that Treasury Secretary Paulson and Housing and Urban Development Secretary Jackson would hold a joint news conference tomorrow afternoon with officials of the mortgage industry.

Treasury also announced that there would be a technical briefing to explain more of the details of the proposal.

Mr. 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 — as a way to make sure that the break is not granted to real estate speculators.

The plan emerged from talks between Mr. Paulson and other banking regulators and banks, mortgage investors, and consumer groups trying to address an avalanche of foreclosures that are feared as an estimated 2 million subprime mortgages reset from lower introductory rates to higher rates.

The higher rates in many cases will boost monthly payments by as much as 30%, making it extremely difficult for many people to keep current with their loans.

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

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

The plan represents an about-face for Mr. Paulson, who until recently had insisted that the mortgage crisis could be handled on a case-by-case basis. However, he and other administration officials became convinced that the tide of foreclosures threatened by the mortgage resets represented such a severe threat that a more sweeping approach was needed along the lines of a plan put forward in October by the head of the Federal Deposit Insurance Corp., Sheila Bair.

Mr. Paulson and other federal regulators began holding talks with some of the country’s biggest mortgage lenders, mortgage service companies, investors who hold mortgage-backed securities, and nonprofit groups that provide counseling for at-risk homeowners.

Under the typical subprime loan, those offered to borrowers with spotty credit histories, the rates for the first two years were at levels around between 7% and 9%. But after two years, those rates were scheduled to reset to levels around 9% to 11%.

For a typical $1,200 monthly mortgage payment, the reset could add another $350 to the monthly payment, greatly raising the risks of loan defaults by homeowners struggling with the current payment.

The wave of mortgage foreclosures threatened to make the most severe slump in housing even worse by dumping more foreclosed properties onto an already glutted market, further depressing home prices and shaking consumer confidence.

The deepening housing slump has already roiled financial markets, starting in August, as investors grew increasingly concerned about billions of dollars of losses being suffered by banks, hedge funds, and other investors.

The administration plan is designed to deal with the crisis by allowing subprime borrowers who are living in their homes and are current on their payments to avoid a costly 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 occurring in many parts of the country.

With sales and prices once again rising, the expectation is that homeowners will be able to renegotiate their current adjustable rate mortgages into a more affordable fixed-rate plan.

The housing crisis has become an issue in the presidential race with Democrats Senator Clinton and John Edwards putting forward their own proposals this week that would go further than the administration.

A chief economist for Moody’s Economy.com, Mark Zandi, said while the administration plan is a good first step, eventually the government will have to go further because of the size of the problem and the threat to the economy.

“This is the most serious housing downturn we have seen in the post World War II period,” he said. “It is a threat to the broader economy. The risks of a recession are very high.”