The chief of Korea's state-run rail operator has resigned over a series of train accidents.

Korea Railroad Corporation CEO Oh Young-sik offered an apology to the nation on Tuesday for failing to fulfill the promise to provide a safe railway service and offered to step down to take responsibility for continued rail accidents.

The resignation comes after a Seoul-bound KTX bullet train carrying 198 passengers derailed in Gangneung, Gangwon Province on Saturday, injuring 16 people.

The KORAIL chief blamed excessive efforts to improve management and efficiency and a massive reduction in rail employees for the recent derailment, adding he hopes the latest accident will serve as an opportunity to address fundamental problems of the nation's railway system.