Chinese regulators have suspended the stock market’s new “circuit-breaker” system that halted trading twice this week amid intense selling. The mechanism most recently kicked in early Thursday after China’s stock markets fell more than 7 percent, halting trades after just 29 minutes.

The China Securities Regulatory Commission said it halted the circuit breaker to “keep the markets stable,” CNBC reported.

Regulators introduced the circuit breaker Monday to prevent dramatic sell-offs, like the one that saw China’s stock market lose 30 percent of its value in less than a month last summer. Under the system, if an index rises or falls by 5 percent, trading is halted for 15 minutes. If the index drops by 7 percent, trading stops for the rest of the day.

The circuit breaker first kicked in Monday after stocks fell 7 percent although the market stabilized Tuesday and rose more than 2 percent Wednesday after China’s central bank reportedly injected some $20 billion in funds to help reassure investors. But Thursday the CSI 300 Index of majors shares plunged 7.2 percent, triggering the circuit breaker for the second time. Shares on the secondary Shenzhen market fell by 8.3 percent before trading was halted.

Analysts said they worried China's limit might kick in too soon, CNBC reported. In the United States, for instance, the S&P 500 stops trading for the day only after the index plunges 20 percent.