US stocks were on pace for their fifth day of losses on Friday, after weak U.S. jobs data in February added to concerns over cooling global growth that was sparked by a sharp fall in China's exports and a prolonged slowdown in the eurozone.
The US economy added just 20,000 jobs in February, compared with expectations of nonfarm payrolls rising by 180,000. The data overshadowed unemployment rate slipping back below 4 percent and the best annual wage growth since 2009.
"The broad selling is because of the very unexpected employment numbers which were much lower that what people had been predicting," said Tom Plumb, chief investment officer at Plumb Funds in Madison, Wisconsin.
"You are starting to see the reasons why the Federal Reserve is not going to be in the tightening at least for the first part of this year because they were starting to see some signs of a slowdown."
The Dow Jones Transports index, closely watched by investors to gauge the health of the economy, dropped 1.60 percent, its steepest in the past 11 sessions of declines.
Worries about global growth intensified after exports in China, the world's second-largest economy, tumbled the most in three years in February, which stirred talk of a "trade recession".
This comes on the heels of the European Central Bank cutting growth forecasts and unveiling a new round of stimulus.
The technology sector fell 0.88 percent and was the biggest drag on the S&P 500, while Facebook Inc, Amazon.com Inc, Apple Inc, Netflix Inc dropped between 0.7 percent and 2.5 percent.
The sector came under pressure after Democratic Senator Elizabeth Warren said if elected president she would seek to break up Amazon, Alphabet Inc's Google and Facebook.
The three main indexes were trading at their lowest since Feb. 14 and were headed for their steepest weekly fall in more than two months after starting the year on a strong note.
At 12:56 p.m. ET, the Dow Jones Industrial Average was down 191.89 points, or 0.75 percent, at 25,281.34. The S&P 500 was down 25.68 points, or 0.93 percent, at 2,723.25 and the Nasdaq Composite was down 66.86 points, or 0.90 percent, at 7,354.61.
The energy sector tumbled 2.44 percent as oil prices dropped about 2 percent and Norway's trillion-dollar sovereign wealth fund said it would drop oil and gas companies from its benchmark index and investment universe.
Oil majors ExxonMobil Corp slipped 2 percent and Chevron Corp dropped 1 percent.
Costco Wholesale Corp jumped 4.56 percent, the most on the S&P, after the warehouse club operator's quarterly profit trumped estimates as margin pressures eased.
Declining issues outnumbered advancers for a 2.28-to-1 ratio on the NYSE and for a 1.73-to-1 ratio on the Nasdaq.
The S&P index recorded five new 52-week highs and five new lows, while the Nasdaq recorded 21 new highs and 46 new lows.