Wal-Mart Stores Inc. (WMT) unsettled the retail industry Thursday, reporting a sales decline for the first time in 10 years and warning that its holiday sales would be disappointing. The discounter's news, coupled with a jump in unemployment benefit claims, raised concerns about the strength of the retailing sector at a critical time of the year.

Wal-Mart's confirmation of weak November sales and its announcement that its December same-store sales gain would be no better than 1 percent came as the nation's retailers reported an overall mixed performance for the month. Same-store sales reflect business at stores open at least a year and are the industry standard for measuring a company's strength.

Wal-Mart's disappointment was a sharp contrast with results from discount rival Target Corp. (TGT), which beat Wall Street forecasts, and Federated Department Stores Inc. (FED), which far exceeded expectations. Other retailers had mixed sales; J.C. Penney Co. (JCP) and Costco Wholesale Corp. (COST) both fell short of Wall Street projections.

Industry analysts generally believed the world's largest retailer is struggling with its own internal problems, not an industry-wide malaise. Still, the discounter's woes raised the possibility that it would incite increasingly aggressive price wars this season that would slice into retail profits. And a Labor Department report Thursday that showed a surprising increase in claims for jobless benefits last week added uncertainty to the outlook for holiday sales.

The timing of Wal-Mart's news couldn't have been worse, coming just after most consumers started holiday shopping. While many retailers had a strong Thanksgiving weekend, Wal-Mart warned Saturday that its November sales would be weaker than expected.

Wal-Mart's 0.1 percent dip in same-store sales for the month is in line with the reduced forecast from analysts surveyed by Thomson Financial, which forecast unchanged growth.

Including a drop in gasoline revenues from its Sam's Club division, which Wal-Mart did not include in its calculation, same store-sales fell 0.3 percent.

Wal-Mart has struggled in recent months with a mix of problems, including the fact that its lower-income customers were hurt by soaring gas prices. But the company's lackluster sales have persisted even as the cost of gas eased, an indication that there are other factors that are dragging down Wal-Mart's results.

"This is pretty discouraging," said Ken Perkins, president of RetailMetrics LLC, a research company in Swampscott, Mass. But he added that Wal-Mart's weak sales "will not be a harbinger of a broad-based weakness across the retail sector."

But he added, "I think it will be a promotional Christmas. Stores will slash prices to drive consumers. And Wal-Mart is going to be first and foremost."

Wal-Mart's discount stores suffered a 0.5 percent decline, while Sam's Clubs had a 2.0 percent increase.

One of Wal-Mart's main problems is that its strategy to broaden its appeal to higher-income shoppers with upscale merchandise was poorly executed. It filled its fall clothing racks with too many trendy items like skinny jeans that shoppers just didn't want.

Wal-Mart's weakness dragged down the International Council of Shopping Centers-UBS same-store sales tally for November to 2.1 percent, below the original 3 percent growth forecast. Excluding Wal-Mart, the tally rose 4.0 percent.

Based on overall disappointing November results, ICSC pared down its growth forecast for the November-December period combined, forecasting a range of 2.5 percent to 3 percent, down from 3 percent.

While retailers have hopes for a decent season, there are concerns about how confident consumers are. The latest measure of confidence by the Conference Board fell during November, and reports of job cuts and buyouts could make consumers even more uneasy.

Thursday's Labor Department report also raised questions about consumers' comfort level.The department said 357,000 claims were filed last week, up 34,000 from the previous week. Economists said it was too soon to tell whether the unexpected increase indicated a weakening in the job market.

October figures on consumer income and spending issued Thursday showed that consumers had reason to be upbeat, at least during that month. The Commerce Department said incomes rose a healthy 0.4 percent, while spending rose 0.2 percent after a decline in September. The data was encouraging but does not guarantee that consumers shopping for the holidays will feel like spending freely — something that was clear the day after Thanksgiving, when shoppers focused on getting the best bargain, gravitating toward early bird specials and then leaving stores when the deals disappeared.

"This tells me that the customers is ever savvy about shopping for markdowns," said John Morris, a managing director at Wachovia Securities "The next couple of weeks will be really telling."

Target's 5.9 percent same-store sales increase topped forecasts of a 5.7 percent gain. But Costco reported a 5 percent gain in same-store sales, below the 5.7 percent estimate.

Among department stores, Federated, which acquired May Department Stores Co. last year, reported a robust 8.5 percent same-store sales gain, beating the 4.8 percent estimate. Same-store sales include only Macy's and Bloomingdale's stores that existed before the deal closed. Federated also raised its December forecast.

Saks Inc.'s 7.2 percent gain in same-store sales beat the 7 percent estimate.

But results from Kohl's Corp. and Penney were disappointing. Penney said same-store sales at its department stores rose 1.4 percent, falling short of the 3.7 percent forecast from Wall Street. Kohl's had a 3.7 percent gain in same-store sales, below the 4.8 percent prediction.

Gap Inc., which is still struggling to find the right fashion formula, suffered an 8 percent drop in same-store sales, worse than the 5.4 percent forecast.

Teen retailers generally did well. Wet Seal Inc.'s 5.5 percent same-store gain beat the 4 percent estimate.