A South Korean marine has killed three of his colleagues and injured two others, BBC reported.
A spokesman for the defence ministry in the capital, Seoul, said the corporal had opened fire while on duty at Ganghwa island west of Seoul.
The shooter was slightly wounded and has been taken into custody, officials said. The motive for the shooting remains unclear.
The island base is near a disputed maritime border with North Korea.
In Monday's incident, a staff sergeant, a corporal and a lance corporal were killed, while a corporal and a private were injured, Yonhap news agency quoted an unidentified military official as saying.
It is unclear whether the perpetrator hurt himself or was injured while being apprehended.
The incident was being investigated, defence officials said.
A spokesman for the defence ministry in the capital, Seoul, said the corporal had opened fire while on duty at Ganghwa island west of Seoul.
The shooter was slightly wounded and has been taken into custody, officials said. The motive for the shooting remains unclear.
The island base is near a disputed maritime border with North Korea.
In Monday's incident, a staff sergeant, a corporal and a lance corporal were killed, while a corporal and a private were injured, Yonhap news agency quoted an unidentified military official as saying.
It is unclear whether the perpetrator hurt himself or was injured while being apprehended.
The incident was being investigated, defence officials said.