Two people have died and two have been injured in an accident involving a 15-ton cargo truck, which crashed into a traffic control office Thursday morning in Jeongseon-gun, Gangwon Province.

As a result of the impact, much of the temporary building was destroyed and fell into the adjacent Jijangcheon, a stream running through the area.

Three people, all employees of the Jeongseon-gun Traffic Management Office, were reported to be inside the temporary structure at the time of the crash.

Among them, a 28-year-old surnamed Ko has died, and the body of a 38-year-old surnamed Na was in the stream after two hours of searching, according to local media reports. Another other employee surnamed Kim, 39, sustained serious injuries, including a fractured pelvis, and has been hospitalized.

The truck, which was carrying lime, also fell into the stream, covering the surrounding areas with lime powder. The driver, 63, reportedly suffered minor injuries and has been taken to hospital.

The driver told police there was a problem with the truck's brakes, saying they failed to work as the vehicle traveled downhill. The police further added that the driver showed no signs of intoxication.

The truck was reportedly overloaded, but an investigation into the incident is still ongoing, an official from the Jeongseon Police Station said in an interview with local media.