Wall Street opens lower on China, North Korea worries

US stocks opened sharply lower on Wednesday after China allowed its currency to weaken further and oil prices slid to their lowest in more than 11 years.

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%, to 16,998.82, the S&P 500 19.19 points, or 0.95%, to 1,997.52 and the Nasdaq Composite 73.90 points, or 1.51%, to 4,817.53.