The Nasdaq Composite was down 16.88 points, or 0.26 percent, at 6,353.58.
"The typical text book trade is that investors rush for safe havens".
Futures markets were also pointing to a lower start for Wall Street, where missile makers have been the only significant gainers in recent days.
The VIX rose further on Wednesday, rising as far as 12.11, its highest in nearly a month.
The VIX, a measure of how much volatility investors expect in stocks, jumped 10.4 percent.
MARKETS OVERSEAS: In Europe, Germany's DAX was down 1.1 percent, while France's CAC 40 fell 1.4 percent.
In other precious metals, silver was almost flat at $16.90 per ounce after hitting its highest since 15 June earlier in the session.
Analysts warned the softening dollar could test June's low of 108.82 yen and even the 2017 trough of 108.13 yen.
Paris and London both lost about one percent, while Frankfurt was flat.
Bargain-seeking investors instead turned their focus to strength in the global economy and earnings toward the end of an active trading day.
The Japanese yen strengthened by 0.5 per cent to around 109.70 per dollar.
Japan is the world's biggest creditor country and there is an assumption that investors there will repatriate funds in a crisis. The dollar was last up 0.3% at 0.9660 francs, while the euro was trading marginally higher at 1.1339 francs. The Swiss currency was also on track for its biggest daily gain against the euro since the Swiss National Bank removed its cap on the currency in January 2015.
Emerging market stocks lost 1.28 percent.
"We saw a tentative recovery in risk appetite yesterday from the sell-off inspired by North Korea but I think justifiably that move is fading a little bit today", said Saxo Bank's head of FX strategy John Hardy.
Stocks ended more than one percent down in Seoul while the won slumped to a three-week low against the dollar as the USA president and South Korea's volatile neighbor dramatically ramped up their war of words. South Korea's Kospi fell 0.2 percent to 2,394.73.
Yields on core government debt fell.
Markets had seen a tentative recovery in risk appetite in U.S. and early Asian trading, but as the war of words resumed Asian stocks dropped back and London, Frankfurt and Paris all lost 0.5 to 1.2 per cent.
Spot gold added 0.7 percent to $1,285.70 an ounce.
Despite the risk-off attitude in the market, stocks in NY were taking back some losses at the London equities close, as bargain hunters entered the market following steep falls in U.S. stock indices earlier this week. Brent crude was up 80 cents at $53.50 a barrel and United States crude was up 60 cents and back up to $50. Bent crude, the global benchmark, rose 19 cents to $52.33 a barrel.