At 9.37am ET (1337 GMT), the Dow Jones Industrial Average was down 49.62 points, or 0.22 per cent, at 22,035.72, the S&P 500 was down 8.01 points, or 0.32 per cent, at 2,466.91.
The dollar weakened after news that US producer prices unexpectedly fell in July, recording their biggest drop in almost a year and pointing to a further moderation in inflation that could delay a Federal Reserve interest rate increase.
Despite its recent weakening, the New Zealand dollar is still up more than 5 per cent this year, setting a 26-month high of $0.7557 in July.
European bourses also looked set to open lower across the board, with Eurostoxx 50 futures already down 0.7 percent in early trade.
Amid this renewed flare-up in tensions with North Korea, Capital Economics chose to take a look at how the precious metal has responded to geopolitical risk events since 1985.
"If you strip away what's going on in North Korea, and if you strip away what's going on in Washington, which are things that are tougher to predict, the economy, the global recovery, earnings, it all paints a very positive picture for the rest of the year", Kravetz said.
North Korea claimed "only absolute force" can work on someone as "bereft of reason" as Trump and detailed plans to fire a salvo of missiles into waters around the US Pacific territory of Guam.
"Military solutions are now fully in place, locked and loaded, should North Korea act unwisely".
He goes on to say: "In all likelihood the North Korea threat will persist for years to come, with the U.S, and increasingly China, attempting to contain and restrain Kim Jong-un".
The North Korea situation isn't the only thing weighing on stocks.
KEEPING SCORE: The Standard & Poor's 500 index fell 7 points, or 0.3 percent, to 2,466 as of 11:20 a.m. The index dropped to a one-month closing low.
Data storage company Seagate Technology (STX) posted a standout gain within the hardware sector, jumping by 2.4 percent.
Meanwhile, the Russell 2000 index of small-cap stocks finished out the week 2.7% lower, its biggest one-week decline since February 2016. The stock has more than doubled over the past 12 months, gaining more than 160%.
Most large-cap stocks fell across the board.
The annual decline in prices stands at 1.7% in July, compared to 1.6 % in June, according to the index, below the 2% target of the federal Reserve. The Japanese markets were closed for a holiday.
Globally, France's CAC 40 share index fell 1.5 percent by the afternoon; Germany's DAX fell 1.3 percent. As a result, the yield on the benchmark ten-year note, which moves opposite of its price, fell by 2.9 basis points to 2.212%. It also raised its outlook. Shares of J.C. Penney dropped 78 cents, or 17%, to $3.93 Friday after the department store's second-quarter loss exceeded expectations.