Sales of existing homes fell for the third time in the past five months in May, with the weakness led by a big drop in demand in the Northeast.

The National Association of Realtors reported Tuesday that sales of previously owned homes dropped by 1.2 percent in May to a seasonally adjusted annual rate of 6.67 million units.

Click here to visit FOXBusiness.com's Real Estate page.

The median price of the homes sold in May rose to $230,000 in May, up 6 percent from the same month a year ago. That represented a slowdown from huge double-digit price gains last year at the peak of the housing boom.

By region of the country, sales fell by the largest amount in the Northeast, a drop of 4.2 percent. Sales were down 3.8 percent in the Midwest.

Sales of existing homes managed to post small gains of 0.7 percent in the West and 0.4 percent in the South.

Analysts said this is a classic pattern for a cooling housing market with sales starting to lag under the impact of rising mortgage rates.

David Lereah, chief economist for the Realtors, said he expected sales to fall by 6.8 percent from last year's record pace. Sales had surged to record levels for five consecutive years as buyers responded to the lowest mortgage rates in four decades.

But with mortgage rates climbing steadily under the impact of credit tightening by the Federal Reserve, analysts look for housing to slow this year but not to crash.

The Realtors report showed that the number of homes still on the market at the end of May climbed to an all-time high for the month of 3.6 million units.

Click here to visit FOXBusiness.com's Real Estate page.