The S&P/Case Shiller composite index of 20 metropolitan areas gained 0.7 percent in October on a seasonally adjusted basis, stronger than the 0.5 percent rise forecast by economists polled by Reuters.

"Looking over this report, and considering other data on housing starts and sales, it is clear that the housing recovery is gathering strength," David Blitzer, chairman of the index committee at Standard & Poor's, said in a statement.

While record low mortgage rates and modest job growth should keep the housing recovery on track, analysts cautioned home prices face downward pressure from a likely pickup in the sales of foreclosed and distressed properties and reduced buying investors and speculators.

Prices in the 20 cities rose 4.3 percent year over year, beating expectations for a rise of 4.0 percent.

Las Vegas posted the biggest monthly rise on a seasonally adjusted basis at 2.4 percent, followed by a 1.7 percent increase in San Diego, the latest Case-Shiller data showed.

"Higher year-over-year price gains plus strong performances in the Southwest and California, regions that suffered during the housing bust, confirm that housing is now contributing to the economy," Blitzer said.

Housing contributed 10 percent to the overall U.S. economic growth in the third quarter, while the sector represented less than 3 percent of gross domestic product, he said.

Last week, the government said U.S. GDP expanded at a stronger-than-expected 3.1 percent annualized pace in the third quarter.

Excluding seasonal factors, however, home prices in 12 of the 20 cities fell in October from September as home values tend to decline in fall and winter, Blitzer said.

Chicago experienced the largest non-seasonally adjusted decline at 1.5 percent, followed by a 1.4 percent fall in Boston.

(Reporting by Richard Leong; Editing by Chizu Nomiyama)

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