An electronic board showing the Korea Composite Stock Price Index at a dealing room of the Hana Bank headquarters in Seoul on Wednesday. (Yonhap)
An electronic board showing the Korea Composite Stock Price Index at a dealing room of the Hana Bank headquarters in Seoul on Wednesday. (Yonhap)

Seoul stocks opened almost flat Thursday as investors sat on the sidelines ahead of the latest rate decision from the US central bank and mounting external uncertainties, including rising oil prices.

After opening a tad lower, the benchmark Korea Composite Stock Price Index was up 0.69 point, or 0.01 percent, to 6,627.95 points, as of 9:15 a.m.

Overnight, stocks on Wall Street closed lower, as investors took a cautious stance over rising oil prices. The S&P 500 closed down 0.45 percent, and the tech-heavy Nasdaq shed 0.78 percent.

A crucial Saudi oil pipeline was struck in an attack and went out of service this week, as Yemen's Houthi rebels seized more islands along Red Sea shipping routes.

Such tensions in the Middle East have pushed Brent Crude futures, the international oil benchmark, up over 2 percent to surpass $108 per barrel Wednesday.

Meanwhile, the yield on 10-year US Treasurys also touched above the 5 percentage point mark for the first time since July 2007, strengthening expectations for the Federal Reserve to deliver a rate-hike decision in its September policy meeting.

In Seoul, market heavyweights were trading mixed.

Top-cap Samsung Electronics traded flat, while its rival SK hynix added 0.95 percent.

Battery maker LG Energy Solution advanced 1.78 percent, and defense giant Hanwha Aerospace inched up 0.28 percent, while carmaker Hyundai Motor retreated 1.23 percent.

The Korean won was trading at 1,365.8 won against the US dollar, down 1.2 won from the end of the previous stock trading session, as of 9:15 a.m. (Yonhap)