A Navy sailor was in critical condition after being hit by a shell accidently fired from a malfunctioning 76 mm-caliber cannon on a guided missile warship in West Sea on Wednesday, military officials said Thursday.

The 21-year-old seaman of the 2nd Fleet Command, identified only by his surname Oh, was in a coma after the shell hit the side of his head, they said. Oh was standing on the deck near the cannon as other sailors tried to remove the shells loaded in the flawed system for safety reasons.

The accident took place some 6.2 kilometers off the coast of Taean, South Chungcheong Province at around 6.20 p.m. He was immediately transported to a nearby hospital and received emergency surgery that night.

“During a live-fire drill on the ship near Uldo Island in West Sea, no shell was able to come out of the cannon for a reason yet to be identified. So, we decided to return to the base,” said a senior Navy official, declining to be named.

“Before reaching the port, we had to remove all the shells loaded into the cannon to ensure that the shells did not explode on the ground. The shell, all of a sudden, was fired and hit the side of Oh’s head.”

The official added that the fired shell exploded in the air and fell into the sea, and that there were no civilian casualties.

The Navy is currently investigating what caused the problem in the cannon, and whether sailors complied with safety regulations concerning the process of removing shells from a malfunctioning weapons system at sea.

The cannon was manufactured in Israel and has been upgraded by a Korean defense firm.

By Song Sang-ho (sshluck@heraldcorp.com)