US stock market futures are falling, with Dow futures down 263 points, S&P futures down 29 points, and Nasdaq futures down 74 points.
Europe is getting smoked, with Britain's FTSE 100 down 1.9%, Germany's DAX down 3.5%, and France's CAC 40 down 2.2%.
The big headline maker was China, where the CSI 300 stock market index crashed 7% before markets were halted for the day.
Japan's Nikkei and Hong Kong's Hang Seng followed China lower, closing down 3.0% and 2.7%, respectively.
New data out of China confirmed that manufacturing in the world's second-largest economy was still contracting. The Caixin-Markit manufacturing PMI unexpectedly fell to 48.2 in December from 48.6 in November. The official NBS manufacturing PMI stood at 49.7 in December. Any reading below 50 signals contraction.
"This shows that the forces driving an economic recovery have encountered obstacles and the economy is facing a greater risk of weakening," Caixin chief economists He Fan said. "More fluctuations in global markets are expected now that the US Federal Reserve has started raising interest rates. The government needs to pay more attention to external risk factors in the short term and fine-tune macroeconomic policies accordingly so the economy does not fall off a cliff."
Perhaps it's the risk of a "fall off a cliff" scenario that has traders and investors rattled.
Elsewhere in the markets, oil continues to trade with a lot of volatility. Oil prices initially spiked by as much as 3.5% after news that Saudi Arabia was severing diplomatic ties with Iran, a sign of escalating tensions between the oil-rich nations. Prices, however, are well off of their highs.