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 shares opened lower Wednesday, as investors sat on the sidelines after Federal Reserve Chairman Jerome Powell fell short of offering more details on the path of the Fed's rate policy.

The benchmark Korea Composite Stock Price Index fell 5.96 points, or 0.21 percent, to 2,861.42 in the first 15 minutes of trading.

Overnight, the tech-heavy Nasdaq composite and the S&P 500 rose to record highs, although the Dow Jones Industrial Average edged down 0.13 percent.

During his congressional testimony, Powell said he is "not going to be sending any signal about the timing of future action," amid growing speculation in the market that a rate cut may happen in September at the earliest.

In Seoul, top tech giant Samsung Electronics fell 0.34 percent, and No. 2 chipmaker SK hynix shed 0.42 percent.

Chemical shares also opened lower, with LG Chem moving down 0.97 percent and AmorePacific losing 0.89 percent.

Carmakers opened mixed, with Hyundai Motors rising 0.73 percent, while its sister Kia lost 0.41 percent.

The local currency was trading at 1,385.7 won against the US dollar at 9:15 a.m., up 4.1 won from the previous session's close. (Yonhap)