South Korea's KOSPI tumbled more than 3 percent on weakness in heavyweight semiconductor shares, triggering a selling sidecar in the main stock market. SK Hynix fell below 2 million won a share during the session.

The Korea Exchange said a selling sidecar, which temporarily halts the effectiveness of program trading sell orders, was triggered on the main board at 10:34 a.m. on Sunday.

The trigger suspended the effectiveness of program trading sell orders for 5 minutes.

A selling sidecar on the main board is triggered when KOSPI200 futures stay down 5 percent or more from the reference price for at least 1 minute.

The KOSPI moved in a narrow range early in the session before falling more than 3 percent as selling pressure widened, led by semiconductor shares.

SK Hynix slid more than 8 percent and fell below 2 million won during the session. It was seen as profit-taking linked to a price gap between its domestic shares and its American depositary receipts after listing the ADRs in the United States on July 10.

SK Square, which holds a stake in SK Hynix, also fell more than 10 percent. Samsung Electronics was down more than 4 percent.

Major semiconductor and information technology stocks, including Samsung Electro-Mechanics, also fell, weighing on the KOSPI.

Sharp swings in the domestic stock market have repeated recently as concerns about a peak in the semiconductor cycle, unstable foreign investor flows and volatility controversy surrounding single-stock leveraged exchange-traded funds overlap.