Seoul: South Korean stocks opened lower Thursday as investors still doubt whether a ceasefire deal between the U.S. and Iran will proceed amid woes over different versions of the agreement terms. The benchmark Korea Composite Stock Price Index (KOSPI) fell 50.72 points, or 0.86 percent, to 5,821.62 as of 9:15 a.m.

According to Yonhap News Agency, on Wednesday, the main index soared nearly 7 percent after Washington and Tehran agreed to the two-week ceasefire, which sharply drove global crude prices lower. Overnight, tensions in the Middle East persisted, with Israel vowing to continue its offensive against Lebanon, stressing that the country is not subject to the ceasefire agreement. Iran said it could withdraw from the ceasefire agreement, including its commitment to keep the Strait of Hormuz open, citing Israel's attacks on Lebanon. Washington said Israel's operations against Lebanon are not covered under the ceasefire agreement, signaling further uncertainties in the crisis.

Investors also worry that the Strait of Hormuz may remain effectively closed as the two sides still spar over the terms. Top market cap Samsung Electronics lost 2.38 percent, and SK hynix moved down 1.84 percent. Construction shares lost ground following the previous session's sharp gains, with Hyundai Engineering and Construction falling 4.03 percent and Daewoo Engineering and Construction losing 0.89 percent.

Leading oil refiner SK Innovation shed 0.33 percent, while S-Oil gained 0.27 percent. Battery makers traded higher, with LG Energy Solution rising 0.99 percent and Samsung SDI moving up 1.17 percent. The local currency was trading at 1,481.7 won against the greenback at 9:15 a.m., down 11.1 won from the previous session.