A soldier of the South Korean Army died on Thursday when a grenade exploded during a training exercise in the Demilitarized Zone along the border with the North, military officials said, suspecting that it could be a suicide.

The Army PFC, identified only by his last name Yang, died when a grenade went off at around 2:20 p.m. Approximately 10 soldiers, including Yang, were engaged in a military drill in the DMZ near the border town when it happened, according to the officials.

The exact cause of the explosion has not been determined, but the military officials suspect that Yang might have committed suicide using his own grenade.

A note he allegedly wrote was reported to have been found later which read, "(This) has nothing to do with (his) military unit."

Military police are currently conducting an investigation into the case, the officials said. (Yonhap)