The housing market may be on the verge of taking another tumble that could weaken the broader economic recovery.

Sales of previously occupied homes dipped in May, even though buyers could receive government tax credits.  And nearly a third of sales in May were from foreclosures or other distressed properties. That means home prices could soon be heading down after stabilizing over the past year.

Last month’s sales fell 2.2 percent from the previous month to a seasonally adjusted annual rate of 5.66 million, the National Association of Realtors said Tuesday. Analysts who had expected sales to rise expressed concern that the real estate market could tumble once the benefit of the federal tax incentives is gone entirely, starting next month.

The report is “a worrisome sign for what will occur in July and thereafter when the effect of the tax credit is behind us,” said Joshua Shapiro, chief U.S. economist at MFR Inc., an economic consulting firm in New York.

Existing-home sales — which account for 90 percent of the housing market — have climbed 25 percent from the lowest level of the recession, an annual rate of 4.5 million sales in
January 2009. But they’re still down 22 percent from the peak rate of 7.25 million in September 2005.

The report counts home sales once a deal closes. So federal tax credits of up to $8,000 for first-time buyers and up to $6,500 for existing homeowners helped prop up sales in May. The deadline to get a signed sales contract and qualify was April 30. Buyers must close their purchases by June 30.

The tax credits were expected to lift sales in May and June. Lawrence Yun, the Realtors chief economist, said delays in the mortgage-lending process put about 180,000 potential buyers in limbo. They are unlikely to qualify by the June 30 deadline. The trade group is pushing Congress to extend the deadline for closing a sale until Sept. 30.

Real estate agents are reporting a decline in foot traffic, meaning sales could worsen in the coming months.

A series of recent industry reports have signaled that the residential real estate market is slowing. Housing starts last month dropped by the most since March 2009, and building permits, a sign of future construction, fell to a one-year low, according to the Commerce Department. The number of mortgage applications filed to purchase houses dropped this month to the lowest level since 1997, according to data from the Mortgage Bankers Association.

Another troubling sign is the number of foreclosures and so-called short sales, which occur when lenders allow borrowers to sell a home for less than they owe on their mortgage.

Existing-home sales have climbed 25 percent from the recession’s low in January 2009 but are still down 22 percent from their peak in September 2005.

Together, foreclosures and short sales made up 31 percent of sales in May. And those numbers ,could rise because the government’s efforts to help troubled homeowners keep their homes have had only modest success.

The inventory of unsold homes on the market dropped 3.4 percent to 3.9 million. That’s an 8.3-month supply at the current sales pace, compared with a healthy level of about six months.

First-time buyers made up 46 percent of sales. The median sales price in May was $179,600, up 2.7 percent from the same month last year.

Although the rise in home prices is encouraging, analysts don’t see that lasting. They say the glut of unsold homes on the market and the anticipated rise in foreclosure sales will drive prices down over the next few months.