The S&P 500 and Nasdaq composite indexes were poised to slip into correction territory, or 10% off their 52-week highs. The Dow Jones industrial average and the Nasdaq 100 slid into a correction zone on Friday.
The Dow was set to open below 16,000 for the first time since February 2014.
The lack of new measures from Beijing to support Chinese stocks following an 11% drop last week sparked a free-fall in global equities and a selloff in oil and commodities.
Oil fell more than 4% to a 6-1/2-year low, while London copper and aluminum futures hit their lowest since 2009.
Oil majors Exxon and Chevron fell about 4% in premarket trading. U.S. oil and gas stocks have already lost about $310 bln of market value this year.
"Until we have some sign that China and the emerging markets aren't being sucked into some vortex from which they can't recover ... it is unlikely this selloff will stem," said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia.
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The dollar index fell 1.1% to $93.92 as the probability of a September rate hike receded.
S&P 500 e-minis were down 76.75 points, or 3.89%, with 1,007,394 contracts traded at 8:08 a.m. ET.
Nasdaq 100 e-minis were down 208.5 points, or 4.96%, on volume of 131,513 contracts.
Dow e-minis were down 685 points, or 4.16%, with 124,196 contracts changing hands.
Wall Street's selloff last week showed investors are becoming increasingly nervous about paying high prices for stocks at a time of minimal earnings growth, tumbling energy prices, and an expected rate hike by the U.S. Federal Reserve.
European stocks were down 4.5%, wiping out more than 400 billion euros ($460 billion) of market value. Asian stocks slumped to 3-year lows as the 3-month-long rout in Chinese equities threatened to get out of hand.
Apple shares slid 5.8% to $99.61 in premarket trading and were set to open at their lowest this year.
Netflix fell 12% to $91.50. Alibaba fell 8.9% to $63.99, well below its IPO price of $68, making it the second high-profile tech company to fall below its IPO price in the past week after Twitter on Thursday.