NEW YORK - A period of relative calm on Wall Street ended yesterday as stocks tumbled in the final hour of trading on investor anxiety ahead of the government's November employment report.

Investors are worried that today's employment report will show a further deterioration in the job market. Economists expect the Labor Department to report that the jobless rate rose to 6.8 percent in November and that companies cut an additional 320,000 jobs.

Jeff Kleintop, chief market strategist at LPL Financial Services, said many institutional investors were bracing for the report to show the economy shed 400,000 jobs last month. He said that a reading below that number could prompt relieved investors to snap up stocks, but that anything worse could touch off further selling.

Yesterday's decline came as the heads of the Detroit automakers appeared before Congress hoping to persuade skeptical lawmakers to provide $34 billion in emergency aid. While the market expects General Motors Corp., Ford Motor Co. and Chrysler L.L.C. to be able to win some aid, a deal is not assured.

The Dow Jones industrials ended down 215.45, or 2.51 percent, at 8,376.24. The Standard & Poor's 500 index fell 25.52, or 2.93 percent, to 845.22, and the Nasdaq composite index fell 46.82, or 3.14 percent, to 1,445.56.

The Russell 2000 index of smaller companies fell 14.23, or 3.14 percent, to 439.53.

Investors earlier had seemed to shrug off a stream of poor economic data. The Labor Department said that new claims for jobless benefits fell unexpectedly last week, but that the number of people continuing to receive government aid reached a 26-year high.

Retailers were the standouts of the session, though the market's late decline pared their gains. The advances came, analysts said, amid relief that huge declines in November sales were not worse.

Macy's Inc. said its same-store sales, or sales at stores open at least a year, fell 13.3 percent. Same-store sales are a key retail measure. Macy's advanced 44 cents, or 5.95 percent, to $7.83. Target Corp. said its same-store sales for the month fell 10.4 percent. The company fell 44 cents, or 1.28 percent, to $34.04.

Many shoppers looking for discounts turned to Wal-Mart Stores Inc. It posted a 3.4 percent increase in sales. Wal-Mart rose 73 cents to close at $55.11.

Among the automakers, GM fell 79 cents, or 16.12 percent, to $4.11, while Ford fell 19 cents, or 6.67 percent, to $2.66. Chrysler is not publicly traded.

AT&T fell 91 cents, or 3.13 percent, to $28.17 after reporting that it is cutting 12,000 jobs, or about 4 percent of its workforce.

Wilmington chemicals-maker DuPont Co. said it would cut 2,500 jobs, mostly serving the U.S. and European automotive and construction markets, because of lower demand. DuPont rose 8 cents to close at $23.69.

Light, sweet crude fell $3.12 to settle at $43.67 a barrel on the New York Mercantile Exchange. Crude, which soared to a record $147.27 in July, is now trading at its lowest levels in four years, having plunged in response to the weakening global economy. The average price of a gallon of gasoline at the pump fell below $1.80, also a four-year low.