Chinese shares tumbled and the yuan weakened as traders returned from an extended holiday amid the worsening coronavirus outbreak. Support measures from China's government helped stem losses somewhat in Asia, while U.S. futures rose and Treasuries slipped.

Stocks in Shanghai opened almost 9 percent lower, while local iron ore and copper futures fell by the daily limit. Equities came off their lows in Tokyo, Seoul and Sydney and fluctuated in Hong Kong. Oil and gold saw modest declines, while the yuan fell past the key 7-per-dollar level.

The deadly outbreak showed no signs of slowing, with China's death toll reaching at least 360.