U.S. pending home sales fell 0.5 percent in February compared to January, the National Association of Realtors said Monday, missing expectations and heightening concerns the real estate market's recovery may not be as robust as thought by economists.

NAR's Pending Home Sales Index, a lead indicator based on contract signings, was down to 96.5 in February from 97 from January. Deals are typically closed within two months of contract signings.

Economists polled by Reuters had expected a 1 percent rise in February, following a 2 percent increase in January.

Despite the unexpectedly weak number, Lawrence Yun, NAR's chief economist, said it was still significantly higher than February 2011's index reading of 88.4.

“The spring home buying season looks bright because of an elevated level of contract offers so far this year,” said Yun. “If activity is sustained near present levels, existing-home sales will see their best performance in five years.

He expects sales to rise 7 to 10 percent in 2012.

Sales in the Northeast were down 0.6 percent to 77.7 in February, but were 18.4 percent above year-ago levels. Midwest sales rose 6.5 percent to 93.8, 19 percent higher than the prior year.

Sales in the South had the largest decline of 3 percent, to 105.8 -- that was 7.8 percent above a year ago. The West had a decline of 2.6 percent in February to 99.3, 1.8 percent below February 2011.