Seoul stocks crashed Tuesday, with the benchmark Kospi tumbling nearly 11 percent as a selloff in chip heavyweights intensified.

The Kospi closed the regular session at 6,023.66, down 10.84 percent from the previous day. Losses mounted from the opening bell, triggering a sell-side sidecar at around 9:06 a.m. and later a circuit breaker as the decline deepened. A sidecar briefly suspends program trading, while a circuit breaker halts all trading.

The index briefly fell as low as 5,992.91, slipping below the 6,000 mark for the first time in nearly 3 1/2 months before recovering to finish just above the threshold.

The rout followed an overnight slide on Wall Street, where major chipmakers including Nvidia, Micron and SanDisk posted steep losses. For Seoul's market, where semiconductor names carry heavy weight in index performance and trading volume, that made Samsung Electronics and SK hynix a focal point of the selloff. Samsung Electronics sank 13.4 percent and SK hynix plunged 14.7 percent.

Foreign investors led the selloff, unloading a net 5 trillion won ($3.42 billion) in Kospi shares, while retail investors bought the dip with net purchases of 4.33 trillion won and institutions bought a net 630 billion won.

The secondary Kosdaq also tumbled, hitting an intraday low of 697.45 before closing 7.7 percent lower at 705.85.

Despite the stock market rout, the won strengthened against the dollar, closing 6 won higher at 1,462.5 per dollar.