Two Seoul subway trains collided on Friday afternoon leaving some 200 passengers injured, firefighters said.

A Line 2 train ran into the back of another that had stalled due to mechanical trouble at Sangwangsimni Station around 3:30 p.m., according to the Seoul Metropolitan Fire and Disaster Headquarters. Passengers said a temporary blackout occurred after the collision.

There were no reported fatalities or heavy injuries, but two passengers and the driver of the second car suffered fractures, the fire department said. 

Of the 200 people who were injured in the accident, 46 went home after receiving medical treatment while 154 remain hospitalized. 

All passengers were evacuated around 3:53 p.m.

The injured were taken to 13 nearby hospitals including Hanyang University Medical Center.Over 200 firefighters, police and government officials were deployed at the scene, along with 58 fire trucks and ambulances.

Witnesses said two carriages were completely separated from the second train.

In an emergency briefing, Seoul Metro said that the signal light for the second train abruptly changed from “go” to “stop,” and the driver was unable to stop in time.

Another official said a device that helps all trains to maintain a safe distance of 200 meters may have been malfunctioning at the time of the accident.

The Ministry of Land, Infrastructure and Transport formed an emergency response team to deal with the accident, headed by Minister Suh Seoung-hwan.

“Although no fatalities have been reported, the ministry formed the team because the number of injuries suggested that the situation was grave,” said a ministry official.

The ministry ordered more buses and taxis to be operated to compensate for shortage in transportation.

Subway operations were partially suspended between Euljiro 1-ga and Seongsu stations.

The accident comes at a time of highlighted safety concerns regarding public transportation. The government has been conducting a comprehensive inspection on 4,000 facilities related to public transportation in the aftermath of the ferry sinking that claimed over 200 lives.

If a mechanical hiccup turns out to be the cause of the accident, it will mark the third time in about a month that a train has broken down because of a technical malfunction.

A similar accident occurred at Busan in 2011, when two trains collided due to a mistake by the driver. Over 100 were injured.

By Yoon Min-sik (minsikyoon@heraldcorp.com)