Contracts for the sale of existing homes rose sharply in February, according to a widely watched industry report released today.

The National Association of Realtors’ (NAR) Pending Home Sales Index rose slightly more than 8 percent in February to 97.6 from a downwardly revised 90.2 in January. The increase surprised economists surveyed by Briefing.com, who were expecting a 1 percent decrease, CNNMoney.com reported.

The increase was a 17 percent improvement over February 2009, when the index was at 83.2.

“The rise in buyer contact activity may signal the early stages of a second surge of home sales this spring,” Lawrence Yun, NAR chief economist, said in a prepared statement. “We need a second surge to meaningfully draw down inventory and definitely stabilize home values.”

The report measures signed real estate contracts, but not completed sales, for existing single-family homes, condominiums and co-ops. Pending home sales are considered a forward-looking indicator, because many of the contracts don’t result in completed transactions for many weeks or months.

The unexpected rise in February could be in response to the home buyer tax credit, the NAR said. Buyers have to ink contracts by the end of April to take advantage of the credit, which offers first-time home buyers up to $8,000 and those who are trading up as much as $6,500.

Last week, the S&P/Case-Shiller Home Price Index of 20 cities showed that home prices have fallen for four consecutive months, following a five-month run-up in prices that started last spring.

Sales of new homes plunged to a record low in February, according to government figures released in March.