South Korean stocks closed lower Thursday, ending a two-session gaining streak, on investor concerns over a second wave of new coronavirus infections in the world's two largest economies. The Korean won rose against the US dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) lost 7.57 points, or 0.35 percent, to close at 2,133.48. Trading volume was moderate at about 754 million shares worth some 10.8 trillion won ($8.9 billion), with winners outnumbering losers 523 to 331.

The drop was mainly attributed to growing investor concerns over the rising COVID-19 tolls in the United States and China.

"The index is likely to remain in the current situation of fluctuating near the 2,200-level, until concerns regarding a second wave of the COVID-19 ease out," Samsung Securities analyst Seo Jung-hun said.

Investors' growing appetite for profit-taking after two winning sessions also kept the index from exceeding the 2,200-level, he added.

Seven states in the US, including Texas, Florida and Oklahoma, posted record highs in either daily or weekly average new infections on Wednesday (US time). The increase fueled fears that the US may consider reintroducing economic lockdowns.

Virus-related tallies also flared in China's capital city this week. The communist state is said to have suspended more than 60 percent of flights to Beijing, while closing down schools and tightening social distancing measures.

Escalating inter-Korean tensions added to investor concerns.

Foreigners sold a net 87.2 billion won, while retail investors purchased a net 149 billion won. Institutions offloaded a net 27.8 billion won.

Large caps traded mixed.

Market bellwether Samsung Electronics retreated 0.19 percent to 52,300 won, while No. 2 chipmaker SK hynix dipped 0.69 percent to 86,200 won.

Top pharmaceutical firm Samsung BioLogics fell 1.70 percent to 810,000 won, with leading chemical maker LG Chem slipping 0.10 percent to 491,000 won.

Internet giant Kakao climbed 0.19 percent to 263,500 won.

The local currency closed at 1,208.00 won against the US dollar, up 5.90 won from the previous session's close. 

Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys lost 3.2 basis points to 0.842 percent, and the return on the benchmark five-year government bond slipped 4.2 basis points to 1.105 percent. (Yonhap)