A KTX bullet train en route to Seoul derailed shortly after departing from Gangneung with 198 passengers aboard today, South Korea's Yonhap news agency reported the operator as saying.

No casualties were reported and 14 passengers suffering from minor injuries were transferred to nearby hospitals.

An official from the Korea Railroad Corp (Korail) said the train left the city, located 237km east of Seoul, and derailed while approaching Jinbu Station at around 7.35am.

The train went off the tracks only around five minutes after departing, passengers said.

Almost all of the train's 10 cars went off the tracks due to a yet-to-be-determined reason, with Korail saying it is carrying out an investigation.

The train was originally set to reach Seoul at 9.30am. The passengers were transferred to other stations by buses.

Korail said other trains are running on a normal schedule from Seoul to Jinbu.

"I was travelling from Gangneung to PyeongChang in the sixth car. But shortly after the train departed, it went off the tracks with a thud," a 22-year-old passenger said.

"It was as if the train slid for around 50 metres, and I could hear the train dragging pebbles with a metallic sound."

The passenger said people were hanging on to their chairs, with some injured people screaming during the accident.

"Even after we got off the train, we had to wait around 50 minutes outside," the passenger added. "I saw an old lady bleeding from her head."

- Bernama