* April nonfarm payrolls up by 160,000 vs 202,000 expected
* Job additions smallest in 7 months
* Square slumps after results miss expectations
* Indexes down: Dow 0.32 pct, S&P 0.31 pct, Nasdaq 0.28 pct (Updates to open)
By Tanya Agrawal
May 6 (Reuters) - Wall Street opened lower on Friday after April payrolls data showed the U.S. economy added the fewest jobs in seven months, raising concerns that the weakness in overall economic activity was spilling over to the labor market.
Nonfarm payrolls increased by 160,000 jobs last month, far below the 202,000 economists polled by Reuters had forecast on average. The number was lower than the first-quarter average monthly job growth of 200,000.
The data cast doubts on whether the Federal Reserve will raise interest rates before the end of the year.
Concerns over mixed economic data and the slowing pace of global growth have clouded the path of interest rate hikes in the United States. The U.S. economy grew just 0.5 percent last quarter on an annualized basis and inflation has been below the Fed's 2 percent target for years.
"It's a disappointing number," said Russell Price, senior economist at Ameriprise Financial Services in Troy, Michigan. "It does show businesses are more concerned about the economic outlook. Demand has been soft, so businesses are responding to that."
At 9:38 a.m. ET (1338 GMT) the Dow Jones industrial average was down 56.56 points, or 0.32 percent, at 17,604.15, the S&P 500 was down 6.35 points, or 0.31 percent, at 2,044.28 and the Nasdaq Composite was down 13.43 points, or 0.28 percent, at 4,703.66.
All 10 major S&P 500 sectors were lower, with the utilities index's 1.17 percent fall leading the decliners.
Traders are also pricing in only one rate hike this year - at the end of the year. The Fed's next meeting is on June 14-15.
An accommodative Federal Reserve and a recovery in oil prices have helped U.S. stocks rebound from sharp losses at the start of the year. However, the rally lost momentum in the past two weeks, weighed by underwhelming quarterly earnings and data.
Oil prices fell over 1 percent as investors cashed in on a 20-percent rise over the past month.
First-quarter earnings for S&P 500 companies are mostly beating analysts' expectations, but are still estimated down 5.3 percent from a year ago, according to Thomson Reuters data.
Shares of Yelp were up 12 percent at $24 after the company's revenue beat expectations.
Endo International slumped 34.7 percent to $17.36 after the drugmaker slashed its 2016 revenue and profit forecasts. The stock dragged other specialty drugmakers, such as Horizon Pharma, Mallinckrodt and Valeant .
Square fell 16.1 percent to $10.96 after the mobile payments company reported a bigger-than-expected quarterly loss.
Declining issues outnumbered advancing ones on the NYSE by 1,616 to 954. On the Nasdaq, 1,318 issues fell and 891 advanced.
The S&P 500 index showed five new 52-week highs and nine new lows, while the Nasdaq recorded seven new highs and 25 new lows. (Reporting by Tanya Agrawal; Editing by Saumyadeb Chakrabarty)