(Corrects paragraph 2 to show Dow didn't close below 10,000 on Thursday, but did slip briefly below that level)

NEW YORK - U.S. stocks fell in choppy trade on Friday as investors struggled to interpret a mixed jobs report, while sovereign debt troubles in the euro zone roiled markets heading into the weekend.

Concerns that governments in Greece, Portugal and Spain may default on their debt hurt the stock market for the second day, after driving the Dow industrials briefly below 10,000 in the last session, when stocks faced their worst daily declines in nine months.

People were drawing comparison between those countries and (failed U.S. investments banks) Bear Stearns and Lehman (Brothers), and that made for a very nervous tape, said Jim Mcguire, Jr., a trader at E.H. Smith Jacobs, in New York.

The concern (is) that we come in Monday morning and the situation may have worsened overseas, and so ahead of that, traders are staying close to shore and not making any big bets for now.

The session's biggest losers included industrial shares, with Boeing Co down 1.9 percent at $58.22, and General Electric Co off 2.9 percent at $15.58.

The Dow Jones industrial average <.DJI> dropped 41.72 points, or 0.42 percent, to 9,960.46. The Standard & Poor's 500 Index <.SPX> fell 4.87 points, or 0.46 percent, to 1,058.24. The Nasdaq Composite Index <.IXIC> lost 0.79 points, or 0.04 percent, to 2,124.64.

The euro fell to its lowest level against the dollar since May, as the cost of insuring Greek, Portuguese and Spanish government debt rose to record highs, and investors sought the perceived safe haven of the greenback.

U.S. crude futures fell more than $3, dropping below $70 a barrel for the first time since mid December, pushed lower by the rallying dollar and pressuring shares of energy companies.

Exxon Mobil Corp fell 0.8 percent to $64.21. An S&P index of energy shares <.GSPE> slid 1.4 percent.

U.S. employers unexpectedly cut 20,000 jobs in January, but the unemployment rate dropped to a five-month low of 9.7 percent, the Labor Department reported before the market's opening bell. And there were substantial revisions to data for the previous months.

The government's nonfarm payrolls report left many investors scratching their heads.

There is some confusion about the numbers and about how different these numbers are. The payroll (report) was clearly disappointing, but the unemployment data was clearly encouraging, said Tim Ghriskey, chief investment officer of Solaris Asset Management in Bedford Hills, New York.

Some positive notes came from the corporate arena.

On the earnings front, U.S. meat producer Tyson Foods Inc reported a much larger-than-expected first quarter profit. Tyson's stock shot up 5.2 percent to $14.72.

Health insurer Aetna Inc offered signs that it was moving toward a turnaround next year. That overcame a disappointing quarterly profit and 2010 forecast, sending the stock up 2.2 percent to $29.85.

(Reporting by Edward Krudy; Editing by Jan Paschal)

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