Stocks opened lower Friday as a weak economic report and more earnings warnings deflated investor optimism just one day after one of the biggest surges on Wall Street in recent years.

The Dow Jones industrial average was off 158.48 at 9,759.57 shortly after the opening of trading. The day before, the index scored its second-largest daily point gain, rising 402.63 after positive earnings news from Dell and Alcoa led to a powerful rally.

Most traces of that optimism were gone early Friday as an after-market warning Thursday afternoon from Sycamore Networks Inc. and another one Friday morning from Tellabs Inc. reset the tone to gloomy.

The Nasdaq composite index was off 52.97 to 1,732.03. The day before, the index had soared 146.20, or 8.9 percent, its third-largest daily percentage gain.

The Standard & Poor's 500 was off 20.10 points in early trading to 1,131.34.

A poor report on the economy also dampened sentiment early Friday.

The Labor Department reported that the unemployment rate rose to 4.3 percent in March, the highest level in 20 months, as businesses cut 86,000 jobs. The payroll reduction was the largest since the end of 1991.

The plunge in payrolls last month marked the first decline since August 2000, and the job weakness was widespread. The report heightened concerns that the economy might topple into a full-blown downturn.

In overseas trading, Japan's Nikkei index rose 2.38 percent in response to the gain in New York. In afternoon trading in Europe, London's FT-SE 100 index was down 0.9 percent, while Frankfurt's DAX index was off 1.21 percent and the CAC-40 index in Paris was down 0.9 percent.