Home foreclosure filings jumped 53 percent in June from a year earlier, although they were down 3 percent from May, and foreclosures are expected to rise further, real estate data firm RealtyTrac said on Thursday.

Foreclosure filings rose on an annual basis in 39 states to a total of 252,363 properties during the month, with Nevada, California, Arizona and Florida posting the highest foreclosure rates.

One out of every 501 U.S. households received a notice of default, auction sale or bank repossession in June, RealtyTrac said.

"June was the second straight month with more than a quarter million properties nationwide receiving foreclosure filings," said James J. Saccacio, chief executive officer of RealtyTrac. "We have not yet reached the top of this foreclosure cycle."

The decrease from May, the first monthly dip since February, was not a fluke but it does not signal a trend, either, said Rick Sharga, vice president of marketing at RealtyTrac, based in Irvine, California, in an interview.

"We were coming off the highest month we ever had in terms of foreclosure activity so some sort of fall-off was inevitable," he said.

It is too early to tell whether the government intervention that slowed the pace of foreclosures will actually prevent foreclosures or merely delay the proceedings, Sharga said.

RealtyTrac sees foreclosure activity peaking at the end of 2008 or the beginning of 2009. At that point, all the risky subprime mortgages due to adjust to more demanding terms will have done so, Sharga said.

The increase in foreclosures has contributed to the plunge in home prices. Prices nationwide fell 3.2 percent in May from April and 20.1 percent from a year ago, according to Integrated Asset Services, a real estate valuation firm that tracks single-family home prices.

Foreclosures add to the supply of homes for sale and also tarnish a neighborhood's image, depressing property values in the immediate area.

The home building industry has already built enough homes for the next 10.8 months, up 21 percent year-over-year, wrote JPMorgan analyst Michael Rehaut in a note to clients.

Nevada had the highest foreclosure rate, with one in every 122 households receiving a foreclosure filing in June, up almost 85 percent from last year at this time.

California had the second-highest rate, with one in every 192 households receiving a filing.

Michigan, Ohio, Colorado, Georgia, Indiana and Utah were the other states in the top 10 as ranked by number of foreclosure filings posted in June.

Efforts by banks and lenders to stall foreclosures have had little impact. Industry alliance Hope Now, which includes big mortgage companies such as Wells Fargo & Co and was created to prevent foreclosures, has helped 1.7 million homeowners in the past year.

In May, mortgage servicing companies negotiated new payment plans with about 100,000 homeowners and changed the terms on another 70,000, Hope Now said last week.

Metropolitan areas in California and Florida had nine of the top 10 cities with the highest foreclosure filing rates, with seven of those in California.

Stockton and Merced in California had the top two spots, while in Florida the top rate was posted by Cape Coral-Fort Myers.

Las Vegas had the sixth-highest rate of foreclosure activity among cities.