An investor looks through stock information at a brokerage house in Huaibei city, East China's Anhui province, Sept 17, 2015. [Photo/IC]

Chinese equities dived on Thursday morning, triggering the 7 percent circuit breaker, which halted trading of equities, index futures and options for the remainder of the day.

In less than 30 minutes after the markets opened, the CSI 300 Index plunged by 7 percent, after resuming from a 15 minute trading halt when it triggered the first trading halt at 9:42 am.

The benchmark Shanghai Composite Index dived by 7.32 percent, heading toward an early closure at 3,115.89 points. The smaller Shenzhen Component Index tumbled by 8.35 percent while the start-up board ChiNext retreated by 8.66 percent.

The market stampede on Thursday sparked growing criticism of the newly introduced circuit breaker mechanism which has been seen as a factor that magnified market volatilities.

"Clearly, the tight stops of 5 and 7 percent has the magnet effect as prices gravitate towards the breaker and prompts a stampede that drains market liquidity," Hong Hao, chief strategist at investment bank BOCOM International said in research note.

The China Securities Regulatory Commission said earlier that it will improve the circuit breaker system based on real market operation.