An electronic board showing the Korea Composite Stock Price Index at a dealing room of the Hana Bank headquarters in Seoul on Monday. (Yonhap)
An electronic board showing the Korea Composite Stock Price Index at a dealing room of the Hana Bank headquarters in Seoul on Monday. (Yonhap)

South Korean stocks fell nearly 6 percent Monday, with the main bourse operator temporarily suspending trading during the morning amid extreme market volatility caused by US-Israeli airstrikes on Iran. The local currency fell sharply against the greenback.

The Korea Composite Stock Price Index surrendered 333 points, or 5.96 percent, to close at 5,251.87.

In the morning, the Korea Exchange activated a circuit breaker, suspending all trading on the main bourse for 20 minutes after the main index stayed 8 percent below the previous session's level for one minute.

It marked the second activation of a circuit breaker since last week, with the KRX issuing one on Wednesday when the KOSPI sank 12.06 percent, the steepest one-day decline since Sept. 12, 2001, in the aftermath of the Sept. 11 terrorist attacks in the United States.

It was the first time a circuit breaker had been activated twice in a single month since March 2020, when the COVID-19 pandemic hit the market.

Shortly after the opening bell, the KRX also activated a sell-side sidecar, suspending sell orders for five minutes. The measure is triggered when the KOSPI 200 Futures index moves 5 percent or more for at least one minute.

The Korean won was trading at 1,495.5 won against the US dollar, down 19.1 won from the previous session, as of 3:30 a.m. (Yonhap)