Train and subway services experienced major delays after a man was fatally struck by a high-speed KTX train bound for Busan on Wednesday.

According to the Korea Railroad Corporation(KORAIL), the state railway operator, an unidentified man entered the tracks between Guro and Gasan Digital Complex stations in Seoul without authorization at around 5:30 a.m. before he was hit and killed by the oncoming train.

The incident forced the train to stop and required adjustments on other tracks that service KTX, regular and subway trains, which share three tracks linking the Line One stations.

While the train in question resumed operation some two hours later, Line One trains were forced to extend the time spent at each station during the morning rush hour to accommodate the readjustments.

Police are looking into the identity of the man and the cause of the incident.