NEW YORK (AP) — Wall Street tumbled Friday after the government said personal incomes fell last month by the largest amount in nearly three years while consumer spending slowed. The Dow Jones industrial average more than 170 points, while a disappointing profit report from computer maker Dell Inc. weighed on the technology-heavy Nasdaq composite index.

Meanwhile, investors charted the path of Hurricane Gustav as it heads toward the Gulf of Mexico and its oil rigs and refineries.

Wall Street's retreat following the downbeat news about consumers also comes after several days of sizable gains in stocks and on the final session before the long Labor Day weekend. Pre-holiday trading is generally light and some pullback was to be expected.

Still, investors were uneasy after the Commerce Department reported that personal incomes fell by 0.7 percent in July — well beyond the drop of 0.1 percent that analysts polled by Thomson/IFR had predicted.

As expected, the government also said consumer spending rose a modest 0.2 percent. That was below the 0.6 percent increase seen in June and, accounting for rising prices, spending fell by 0.4 percent in July. Wall Street has been concerned about Americans' ability to help the economy grow, as high prices for gas and food have strapped many household budgets.

"My biggest concern with the income data is that we're getting off to a weak start to the third quarter," said Robert Dye, senior economist at PNC Financial Services Group. "The income numbers are a reminder that the economy is going to look worse before it gets better."

According to preliminary calculations, the Dow Jones industrial average fell 171.22, or 1.46 percent, to 11,543.96. The blue chips began trading Friday having logged a three-day advance of nearly 330 points.

Broader stock indicators also lost ground. The Standard & Poor's 500 index fell 17.85, or 1.37 percent, to 1,282.83. The Nasdaq fell 44.12, or 1.83 percent, to 2,367.52.

For the week, Dow fell 0.99 percent, the S&P 500 lost 1.18 percent and the Nasdaq fell 3.47 percent.

Declining issues outnumbered advancers by nearly 2 to 1 on the New York Stock Exchange, where volume came to a weak 959.1 million shares compared with 956.2 million shares traded Thursday. Trading has been light all week, prompting some observers to dismiss the market's moves as aberrations that occur when many traders are on vacation.

Bond prices fell Friday. The 10-year note's yield, which moves opposite its price, rose to 3.83 percent from 3.79 percent late Thursday. The dollar was mixed against other major currencies, while gold prices fell.

Light, sweet crude fell 13 cents to $115.46 per barrel on the New York Mercantile Exchange. While oil trading has been orderly as Gustav progresses, there is concern about damage from the storm or a disruption in the flow of gasoline and other fuel from Gulf Coast refineries.

Although many investors are fixated on consumers, Wall Street showed little reaction to the Reuters/University of Michigan's index of consumer sentiment, which rose to its highest level in five months. Economists often reason that consumers who are upbeat about their prospects are more likely to spend.

Also, investors shrugged off the Chicago Purchasing Managers' index, which measures business conditions across Illinois, Michigan and Indiana. It jumped to 57.9 from 50.8 in July. The index is considered a precursor to the Institute for Supply Management's manufacturing survey on Tuesday. Investors also will be looking next week to readings on the service sector, construction, factory orders and employment.

"Traditionally September is a weak month for stocks and I don't think we're going to escape that," said Peter Cardillo, chief market economist at New York-based brokerage house Avalon Partners Inc., looking to the coming week. "I do think we are going to stay in a trading range. I don't see this market falling out of bed and going below the July lows."

But concerns that arose Friday could remain next week. Investors worried about the tech sector after Dell's report late Thursday and its cautious comments about spending in the sector. The stock fell $3.48, or 14 percent, to $21.73.

Another tech name, Marvell Technology Group Ltd., fell after its third-quarter revenue forecast fell short of Wall Street's estimate. The stock lost 65 cents, or 4.4 percent, to $14.11.

Friday's slide came as many traders were squeezing in last-minute summer holidays. The stock market's moves during the week perhaps belied the quiet surrounding some trading posts. While readings on the overall economy as well as consumer confidence and demand for big-ticket manufactured goods were better than expected, volume remained light, which can skew price moves. After tumbling Monday on worries about the credit markets and finishing mixed Tuesday, stocks rose Wednesday and Thursday.

The Russell 2000 index of smaller companies fell Friday to 8.29, or 1.11 percent, to 739.50.

In Tokyo, the Nikkei index rose 2.39 percent. In Europe, London's FTSE-100 index rose 0.63 percent, Frankfurt's DAX rose 0.03 percent and the CAC-40 index in Paris rose 0.47 percent.