WASHINGTON - Fewer Americans than expected signed contracts to purchase previously owned homes in January, indicating the extension of a tax credit is doing little to lure buyers.

The index of purchase agreements, or pending home sales, dropped 7.6 percent after a revised 0.8 percent increase in December, the National Association of Realtors announced in Washington. Other reports Thursday showed factory orders increased and first-time jobless claims declined.

The drop in contract signings adds to evidence that the housing market at the center of the worst recession since the 1930s is struggling to rebound after reports last week showed unexpected declines in purchases of new and existing homes. The market may get another blow this month when the Federal Reserve ends planned purchases of mortgage-backed securities.

"When you take away all the support from the housing market, the underlying demand for housing is a lot weaker than we thought," said Mark Vitner, a senior economist at Wells Fargo Securities in Charlotte, N.C. "We clearly pushed some demand forward, and there wasn't that much demand to pull forward anyway. The housing recovery is going to be very, very slow."

The Realtors' report showed declines in January pending sales in all four regions, led by a 13 percent slump in the West. Contract signings fell 8.9 percent in the Midwest, 8.7 percent in the Northeast and 2.1 percent in the South.

Pending home sales are considered a leading indicator because they track contract signings. The Realtors' existing-home sales report tallies closings, which typically occur a month or two later. The pending sales data go back to January 2001, and the group began publishing the index in March 2005.