Stocks plunged further on Tuesday to extend the steepest four-day rout since 1996 on concern that authorities are withholding market support measures. The benchmark Shanghai Composite Index sank 7.6 percent to close at 2,964.97, falling below the 3,000 level for the first time in eight months. The gauge has lost 22 percent over the past four days.

Mainland Chinese stock markets unexpectedly slumped again on Tuesday, with the primary index for the Shanghai market plunging by 6.2 percent. The stock sell-off was the steepest since an 8.5 percent decline in Shanghai on July 27, which was the market's biggest daily drop in eight years.

Stocks in China posted their biggest one-day gain in a month after weak economic data lifted expectations Beijing would boost spending and continue to prop up the market by buying shares.