One in 10 residential mortgages in the U.S. was at risk of foreclosure this summer, the Washington-based Mortgage Bankers Association said Thursday.

About 9.9 per cent of homeowners had missed at least one mortgage payment as of June 30, it said.

Americans behind in their mortgage payments line up in Miami Beach in April to negotiate better terms with their bankers. (Tim Chapman/Associated Press/Miami Herald)

That number, which is adjusted for seasonal factors, was down slightly from a record high of more than 10 per cent as of April 30.

As well, the percentage of mortgage borrowers receiving foreclosure notices fell slightly, to 4.57 per cent, in the three months ending in June quarter.

That was down from 4.63 per cent in preceding quarter and the first drop in four years.

In a worrisome sign, however, the number of homeowners starting to have problems with their mortgages rose after trending downward last year.

Home loans overdue by a month rose to 3.51 per cent from 3.45 per cent in the first quarter.

"Ultimately, the housing story, whether it is delinquencies, homes sales or housing starts, is an employment story," Jay Brinkmann, the association's top economist, said in a statement.

"Only when we see a consistent increase in employment will we see an increase in sales and starts, and a sustained improvement in the delinquency numbers."

With files from The Associated Press