Over 10 people were injured on Thursday when an escalator at Sunae Station on the Bundang Line suddenly began operating in reverse.

The incident was reported to the South Korean Fire Service at around 8:20 a.m., with multiple injuries caused by the malfunctioning escalator at Exit No. 2 of the station.

According to the fire department, three individ­uals who sustained serious injuries were hospitalized, while 11 others who suffered minor injuries were sent home after receiving medical treatment.

Later in the afternoon, the Korea Railroad Corporation released a statement with an apology.

Korail promised to spare no effort in improving its safety inspection and facility maintenance procedures, as well as preparing proper measures to prevent any recurrences.

In addition, Korail said it would overhaul all escalators in subway stations across the nation and continue investigating the incident through a joint inspection with the Korea Elevator Safety Agency, an affiliate of the Ministry of Public Administration and Security.

According to Korail, the escalator was installed in 2009, and a supplementary emergency brake was added in 2020.

It was reported that the escalator was assessed as “in normal operation” during a recent overhaul by a maintenance company in May. The KESA also found that the elevator had "no problem" during a regular overhaul last year.

Along with Korail, the Ministry of Land, Infrastructure and Transport announced that it would conduct an in-depth investigation into the incident. The ministry said it would look into the maintenance system including the overhaul cycle, conformity to safety regulations and any possible breach of the Railroad Safety Act.