SEOUL, March 4 (Xinhua) -- South Korea's bourse operator triggered circuit breakers on Wednesday after a bout of panic selling amid escalating Middle East conflict.

The benchmark KOSPI tumbled 468.98 points, or 8.10 percent, to 5,322.93, and the smaller KOSDAQ plunged 92.46 points, or 8.13 percent, to 1,045.24.

The Korea Exchange triggered circuit breakers on both the KOSPI and KOSDAQ markets following the severe market crash, caused by the escalating geopolitical tensions in the Middle East.

The level 1 circuit breaker was activated in the KOSDAQ at 11:16 a.m. local time (0216 GMT), and the circuit breaker was also issued in the KOSPI about three minutes later.

A level 1 circuit breaker will be triggered when the index drops more than 8 percent for at least one minute to suspend trading for 20 minutes, while a level 2 will be activated when the index plunges 15 percent or more for over one minute to halt trading for 20 minutes.

After the 20-minute suspension, trading resumes following a 10-minute single-price auction period.

A level 3 circuit breaker will be triggered when the index drops 20 percent or more and the trading is closed for the day.

The South Korean won versus the U.S. dollar exchange rate stayed at 1,480.30 won per dollar at 11:00 a.m. local time, up 14.20 won from the previous day's daytime close.

Foreign investors led the sell-off in the KOSPI, while retail and institutional investors prevented a deeper rout through dip-buying in the KOSPI. ■