South Korean shares closed almost three percent lower on Thursday, hit by concerns China might move more aggressively to cool its fast-growing economy and record foreign selling of local stocks that slammed key exporters such as Samsung Electronics and POSCO.
Speculation about a possible rise in US interest rates also encouraged foreign players to sell, analysts said.
Foreigners dumped a net 772.7 billion won ($670.7 million) worth of local shares, more than double the previous daily record of 376 billion won hit in August 2002.
The benchmark Korea Composite Stock Price Index (KOSPI) finished 2.93 percent lower at 875.41, its lowest close in almost a month. The index had earlier fallen as much as 3.24 percent during the day.
Chinese Premier Wen Jiabao said in an exclusive interview with Reuters on Wednesday forceful measures were needed to cool China's fast-growing economy.
Memory chip maker Samsung tumbled 4.32 percent to 576,000 won and POSCO, the world's fourth-biggest steel maker, shed 5.77 percent to close at 147,000 won.
On the main stock exchange, trade volume reached 437 million shares on turnover of 3.4 trillion won, against 373 million shares worth 2.6 trillion won on Wednesday.
Decliners trounced advancers by 570 to 173 with 53 titles ending flat.
Domestic institutions bought a net 384 billion won in shares and retail investors bought a net 195 billion won of shares.
The junior Kosdaq slid 4.73 percent to 456.04 points.
The June KOSPI 200 futures index fell 3.10 points to 114.65 and the underlying KOSPI 200 spot index dropped 3.47 points to 114.01.