"Unfortunately the markets haven't come to grips with the current levels of trade policies and tariffs," said Art Hogan, chief market strategist at B. Riley FBR in New York.
"Concerns over trade and trade wars are really having an adverse effect, less so on the U.S. markets than the international markets, but it is certainly taking a bite."
The Dow Jones Industrial Average fell 219.21 points, or 0.88 percent, to 24,700.45, the S&P 500 lost 19.82 points, or 0.71 percent, to 2,774.02 and the Nasdaq Composite dropped 42.59 points, or 0.55 percent, to 7,716.61.
In currencies, both the yen and the dollar act as safe-haven investments. But the strength of the greenback against the yen suggests investors are reflecting faith in the U.S. economy rather than seeking safety.
The dollar index rose 0.6 percent, with the euro down 0.59 percent to $1.1673.
The Japanese yen weakened 0.92 percent versus the greenback at 112.02 per dollar.
In Europe, shares extended losses after Trump kicked off a NATO summit in Brussels by accusing Germany of being a "captive" of Russia.[.EU]
Australia's dollar, often seen as a proxy for China's economic fortunes due to Australian raw materials exported there, extended losses and was last down 1.21 percent. [/FRX]
Industrial metals copper, zinc and lead all slumped as much as 4 percent to their lowest levels in about a year over worries that the trade dispute could dent China's commodity-hungry economy. [MET/L]
Copper lost 3.12 percent to $6,135.00 a tonne.
Three-month aluminium on the London Metal Exchange lost 1.41 percent to $2,060.50 a tonne.
Oil also fell on news that Libya would reopen its ports, raising expectations of a growing supply.
U.S. crude fell 4.71 percent to $70.62 per barrel and Brent was last at $74.12, down 6.01 percent on the day.
Graphic - Global assets in 2018: http://tmsnrt.rs/2jvdmXl
Graphic - Emerging markets in 2018: http://tmsnrt.rs/2ihRugV
Graphic - World FX rates in 2018: http://tmsnrt.rs/2egbfVh
Graphic - MSCI All Country World Index Market Cap: http://tmsnrt.rs/2EmTD6j
(Reporting by Hilary Russ in New York, additional reporting by Amy Caren Daniel in Bengaluru and Jessica Resnick-Ault and Kate Duguid in New York; Editing by Nick Zieminski and Rosalba O'Brien)
© Reuters News 2018