WASHINGTON — Sales of new U.S. homes plunged in June, a sign that real estate continues to be a weak spot in the economy.

New home sales fell 8.1 percent last month to a seasonally adjusted annual rate of 406,000, the Commerce Department said Thursday. The report also revised down the May sales rate to 442,000 from 504,000.

Buying of new homes fell 20 percent in the Northeast, followed by less extreme declines in the Midwest, South and West.

Data on new housing construction in Maine is scheduled to be released Friday.

But at least one indicator suggests that one sector – sales of existing homes – is robust in Maine, a trend Realtors said was driven by an influx of new residents and pent-up demand from the harsh winter.

Sales of existing single-family homes in June jumped by 14 percent compared to June 2013, according to Maine Listings, a subsidiary of the Maine Association of Realtors.

That bucks what’s happening nationwide. Across the United States, sales of new and existing single-family homes dipped by 2.9 percent in June, according to the National Association of Realtors.

The modest sales nationally caused the inventory of new homes on the market to increase to 5.8 months, the highest since October 2011.

The median sales price was $273,500, up 5.3 percent over the past 12 months.

“Today’s report underscores” Federal Reserve Chair Janet Yellen’s “observation in testimony last week that housing sector data still are ‘disappointing,”‘ said Dana Saporta, director of economic research at the bank Credit Suisse.

Home sales had been improving through the middle of 2013, only to stumble over the past 12 months due to a mix of rising prices, higher mortgage rates and meager wage growth.