South Korea's bourse operator said Wednesday it is yet to be decided whether stock markets will open as usual following President Yoon Suk Yeol's unexpected emergency martial law declaration.

Yoon declared martial law in a previously unannounced late-night address Tuesday, accusing the opposition side of controlling the parliament and paralyzing the government by conducting "anti-state activities."

"It is yet to be decided if the stock markets will be opened Wednesday," a Korea Exchange official said.

The benchmark Kospi and tech-heavy Kosdaq markets are scheduled to open at 9 a.m. and close at 3:30 p.m. (Yonhap)