U.S. stock index futures indicated a lower open on Friday as traders eyed comments from a series of Fed speakers.
Dow futures were down more than 100 points, while S&P and Nasdaq futures dropped 12 points and 29 points, respectively.
Boston Fed President Eric Rosengren said in a speech low interest rates are increasing the chance of overheating the U.S. economy. Gradually tightening monetary policy is appropriate to maintaining full employment, he added.
U.S. Federal Reserve Governor Daniel Tarullo will be on CNBC at 10 a.m. Eastern. There is also an appearance by Dallas Fed President Rob Kaplan at the Mission Capital conference in Austin scheduled for Friday. Kaplan also speaks in the evening at the Dallas Security Traders Association convention.
In Asia, Friday saw North Korea claim it had tested a miniaturized nuclear warhead as protection against "threats and sanctions" from hostile elements, according to the state's official news agency. South Korea's KOSPI finished 1.25 percent lower.
Japan's Nikkei closed essentially flat — 0.04 percent higher — on Friday, while in China the Shanghai Composite closed 0.55 percent lower.
In Europe, the pan-European Stoxx-600 index fell 0.37 percent.
In oil markets, Brent crude traded at $49.23 a barrel on Friday, down 1.5 percent, while U.S. crude held at $46.96 a barrel, down 1.4 percent.
On the data front, wholesale trade is due at 10 a.m. ET. On the earnings front, Kroger reported mixed quarterly results.
—CNBC's Patti Domm contributed to this report