The price of single family homes in the 20 biggest U.S. metropolitan areas rose in April by 0.7 percent over the preceding month, the first monthly increase in eight months, according to the Case-Shiller report released Tuesday by Standard and Poor's.

"In a welcome shift from recent months, this month is better than last - April's numbers beat March," David M. Blitzer, chairman of the Index Committee at S&P Indices, said in a statement accompanying the data.

This index, prepared by S&P to reflect the evolution of housing prices in the 10 and 20 largest American cities, noted increases in April of 0.8 percent and 0.7 percent, respectively.

But if compared with April 2010, home prices dropped 3.1 percent and 4 percent this April, so that the current home prices in the United States are roughly at the same level as in the summer of 2003, long before the housing bubble burst.

Seasonally adjusted numbers "show that much of the improvement reflects the beginning of the spring-summer home buying season," Blitzer said. "It is much too early to tell if this is a turning point or simply due to some warmer weather."

In April, only seven of the 20 biggest metro areas showed monthly price decreases: Detroit, Las Vegas, Chicago, Tampa, Charlotte, Boston and Miami.

On the contrary, if compared with 2010, only Washington, with a gain of 4 percent, registered an increase in home prices.

"For a real recovery we would need to see several months of increasing home prices, large enough to shift the annual momentum to the positive side. In short, better news, but still a lot of questions and a long way to go," S&P's Blitzer said.

Since reaching their highest point in summer 2006, home prices in the 20 largest U.S. metro areas show an accumulated decline of more than 32 percent.