U.S. home prices rose strongly for the third-straight month in June, pushing prices up 3.6% during the second quarter from a year earlier, according to the S&P Case-Shiller home-price indexes, thanks to boosts from a winding-down government tax credit for homebuyers.

However, the year-to-year increases decelerated in June from May after 16 straight months of improving results, “pointing to a possible deceleration in home price returns.”

Before prices began rising in April, prices had fallen sequentially for six straight months by the S&P/Case-Shiller measures.

“While the numbers are upbeat, other more recent data on home sales and mortgages point to fewer gains ahead,” said David M. Blitzer, chairman of S&P’s index committee. But he also noted that “even with concerns about near-term developments, we recognize that the housing market is in better shape than this time last year.”

Renewed worry about the housing market comes as economists downgrade their forecasts for the economy this year and early next year. Traditionally, the housing sector, along with purchases of durable goods such as furniture, would help pull the economy out of a recession as lower interest rates spur higher demand. But the sector hasn’t seen improvement of late, with unemployment remaining high and the tax credit’s benefits wearing off.

Sales of previously owned homes are on the skids, plummeting 27% in July to levels not seen in more than a decade as the effects of the tax credit wane, the National Association of Realtors said last week.

The Case-Shiller 10-city and 20-city major metropolitan area indexes each rose 1% in June compared with May. The 10-city index rose 5% and the 20-city index climbed 4.2% from year-earlier levels.

The U.S. National Index — a broader measure of prices that is only released quarterly, rose 4.4% from the prior quarter and 3.6% from a year earlier.

Month-to-month gainers were headlined by Chicago, Boston and Minneapolis on an unadjusted basis, as all rose 2.5% from a month earlier. The only declining market month-over-month was hard-hit Las Vegas, which dropped 0.6%.