Chinese shares tumble over three percent

Chinese shares tumbled heavily on Friday, with the benchmark Shanghai Composite Index nosediving more than three percent.

The smaller Shenzhen index opened 0.73 percent lower at 10,268.95 points, Xinhua news agency reported.

The ChiNext Index, tracking China's NASDAQ-style board of growth enterprises, lost 0.68 percent to open at 2,160.17 points.