Stock futures fall on China worries, North Korea nuclear test

Geopolitical concerns were also heightened after North Korea said it had tested a hydrogen bomb and Saudi Arabia cut ties with Iran.

The Dow Jones industrial average fell 159.84 points, or 0.93 percent, to 16,998.82, the S&P 500 19.19 points, or 0.95 percent, to 1,997.52 and the Nasdaq Composite 73.90 points, or 1.51 percent, to 4,817.53.

(Reporting by Sai Sachin R in Bengaluru)