LOS ANGELES - 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 yesterday.

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 that 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.

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.

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.

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.

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.