Sales at U.S. retailers rose 4.5 percent last week from a year earlier, as shoppers snapped up last minute purchases for Christmas and took advantage of some chains extending hours.

Sales for the week ending Dec. 24 increased 0.9 percent from the previous week, according to a chain-store sales index released today by New York-based International Council of Shopping Centers and Goldman Sachs Group Inc. That compared with a 3.4 percent gain a week earlier.

Retailers benefited from Christmas Eve falling on a Saturday, with Family Dollar Stores Inc., Toys “R” Us Inc. and Macy’s Inc. among chains extending hours to lure bargain-hunting shoppers. Unemployment at its lowest in more than two years and falling gasoline prices boosted consumer confidence to an eight- month high in December, prompting households to seek discounts during the holiday season.

“Holiday shopping went down to the wire as consumers took advantage of the full shopping week ahead of Christmas Day, which fell on a Sunday this year,” Michael Niemira, ICSC’s chief economist, said in the statement. Gift-card redemption in coming weeks “could be stronger than in recent years,” he said.

The ICSC reiterated its forecast for December comparable- store sales to rise 3.5 percent to 4 percent.