Three Marines were injured Tuesday as a hand grenade exploded during a training session at a Marine unit in this southeastern port city, military sources said.

The accident took place around 10:20 a.m. at a drill camp of the South Korean Marine Corps as a hand grenade suddenly exploded, cutting off the wrist of one Marine with shrapnel wounding two others, they said.

The injured Marines were all were taken to a hospital and they were listed in stable condition, the sources said.

The military is investigating the cause of the explosion, they added.

The blast is the latest in a series of accidents that have hit the South Korean military in recent months.

In early September, two noncommissioned officers in the Special Warfare Command died while undergoing a training exercise, meant to simulate enemy captivity, in the country's central town of Jeungpyeong, some 126 kilometers south of Seoul. (Yonhap)