LOS ANGELES (AP) -- Households across a majority of large U.S. cities received more foreclosure warnings in the first six months of this year than in the first half of 2009, new data shows.

The trend is the latest sign that the nation's foreclosure crisis is worsening as homeowners battling high unemployment, slow job growth and an uneven rebound in home prices continue to fall behind on their mortgage payments.

In all, 154 out of 206 metropolitan areas with at least 200,000 residents posted an annual increase in foreclosure activity between January and June, foreclosure listing firm RealtyTrac Inc. said Thursday.

The firm tracks notices for defaults, scheduled home auctions and home repossessions -- warnings that can lead up to a home eventually being lost to foreclosure.

The latest figures show the threat of foreclosures is spreading well beyond the top tier of metropolitan areas located in California, Florida, Nevada and Arizona, which have borne the brunt of the fallout from the housing crisis.

Those states saw housing values surge during the housing boom years. When the boom ended, values collapsed and foreclosures soared.

"The face of foreclosure is driven much more now by unemployment than in the past, and it's moving out from the places where we've been focusing on in the last few years," said Rick Sharga, a senior vice president at RealtyTrac. "The combination of a weak job market and a weak housing market is making it difficult in some of these areas."

The Miami-Fort Lauderdale-Pompano Beach metropolitan area in Florida received more foreclosure-related warnings in the first half of this year than any other, the firm said.

Florida accounted for nine of the top 20 metro areas with the highest foreclosure rates.

The latest data echo broader, national foreclosure trends.

The number of households facing foreclosure in the first half of the year climbed 8 percent versus the same period last year, but dropped 5 percent from the last six months of 2009, RealtyTrac said in a report issued earlier this month.

In all, about 1.7 million homeowners received a foreclosure-related warning between January and June. That translates to one in 78 U.S. homes.

More than 1 million American households are likely to lose their homes to foreclosure this year, the firm said.

The latest data included one bright spot: Nine of the top 10, hardest-hit metropolitan areas saw their foreclosure rates drop from a year ago. That could suggest foreclosure trends in those cities, including Las Vegas, Cape Coral, Fla., and Modesto, Calif., may have peaked.

"We probably won't know that for sure for another six months," Sharga said.

Still, those areas continue to see foreclosure rates that are as much as five times higher than the national average.

The top 10 metropolitan areas with the highest foreclosure rates has remained fairly unchanged over the past 12 months.

The Las Vegas-Paradise, Nev., metropolitan area topped the list with one in every 15 homes receiving a foreclosure warning in the first half of the year -- five times the national average. But foreclosure filings declined nearly 9 percent versus the first six months of 2009.

Rounding out the rest of the top 10 metros with the highest foreclosure rate in the first half of 2010 were Cape Coral-Fort Myers; Modesto; Merced, Calif.; Riverside-San Bernardino-Ontario, Calif.; Stockton, Calif.; Phoenix-Mesa-Scottsdale, Ariz.; Orlando-Kissimmee, Fla.; Vallejo-Fairfield, Calif.; and Miami-Fort Lauderdale-Pompano Beach, Fla.

The Miami-area metro was the only one among the top 10 to register an annual increase in its foreclosure rate.