South Korea's KOSPI fell more than 6 percent and dropped below the 6,000 level in intraday trade. It was the first time the index traded below 6,000 intraday since it regained the level on July 31.

The Korea Exchange said the KOSPI extended losses early in the session and slipped below 6,000. It was the first time the index fell below 6,000 intraday since July 31.

The sharp decline triggered a sell-sidecar in the main board market.

The Korea Exchange suspended the effectiveness of program sell orders for 5 minutes after KOSPI 200 futures stayed down 5.08 percent from the reference price for more than 1 minute at 9:47:58 a.m.

South Korean stocks have recently undergone a sharp correction led by semiconductor shares.

In the U.S. market on Oct. 12 (local time), semiconductor shares such as Micron and SanDisk plunged after a plan by Chinese memory maker CXMT to launch next-generation DDR5 for servers became known, and the Philadelphia Semiconductor Index fell 2.7 percent.

The KOSPI is down a cumulative 8.9 percent after falling for 4 straight sessions through the previous trading day.

Han Ji-young (한지영), an analyst at Kiwoom Securities, said weakness in semiconductor shares driven by China could increase volatility early in the session. She said it was also necessary to watch whether the rise in U.S. long-term yields eases and whether bargain-hunting emerges after consecutive steep declines.