Lee Eog-weon, chairman of the Financial Services Commission (FSC), speaks during a parliamentary committee session at the National Assembly in Seoul, Wednesday. Yonhap

The chief financial regulator on Wednesday expressed regret over recent extreme market volatility, saying the authorities take responsibility for the turmoil amid criticism that single-stock leveraged ETFs had amplified the market swings.

"I regret failing to fully meet the public's expectations," Lee Eog-weon, chairman of the Financial Services Commission (FSC), said during a session at the National Assembly. "I take the sharp rise in market volatility very seriously."

It marked the first time the FSC chairman apologized in public over the controversy surrounding single-stock leveraged ETFs.

"As the agency is ultimately responsible for the financial market, we recognize our heavy responsibility," Lee said. "We plan to promptly implement supplementary measures and introduce additional steps if necessary."