European stocks closed higher for a third straight session on Friday, boosted by a news report saying the European Central Bank will likely wait until December to unveil a plan to taper its asset purchases. Softer-than-expected U.S. jobs data also helped spur a positive mood on the stock markets, as they were seen as weakening the case for the Federal Reserve to raise interest rates again this year.

U.S. stock-index futures fell Monday, with analysts blaming the drop on renewed worries about North Korea after the isolated nation conducted its largest-ever nuclear test. Futures for the main equity benchmarks were declining alongside European and Asian markets, putting the market on track for a selloff at Tuesday's open, as American stock exchanges are closed Monday for Labor Day.

Most Asian stock markets fell for a second day Tuesday as South Korea carried out military exercises amid mounting official criticism of North Korea's weekend nuclear test explosion. South Korean warships conducted live-fire exercises at sea following U.S. warnings of a "massive military response" after North Korea's nuclear test. The U.N. Security Council held an emergency meeting and American Ambassador Nikki Haley said North Korean leader Kim Jong Un is "begging for war."