SEOUL, Korea, Republic Of - South Korea's top court on Friday upheld a death penalty for a soldier convicted of killing five comrades in shooting and grenade attacks in a front-line army unit in 2014.

The verdict by the Supreme Court is final and cannot be appealed, a court official said, requesting anonymity because of department rules. The Defence Ministry said it confirmed the court's ruling.

The conscript, only identified by his surname Yim, had told investigators after his arrest that he assaulted fellow soldiers because he felt insulted by drawings they made of him. He had fled into the forest near the border with North Korea but was captured after a failed suicide attempt.

South Korean courts occasionally issue death sentences but the country has not executed anyone since December 1997. Yim has become the 61st person in South Korea on a death row, according to records from the Justice Ministry and the Defence Ministry.

South Korea requires all able-bodied men to serve in the military for about two years in the face of a threat from North Korea. Shooting rampages by bullied soldiers in South Korean army barracks are not unusual. In 2005, another soldier went on a similar rampage and killed eight colleagues in anger at superiors who he said verbally abused him. He too was sentenced to death.

Such rampages raised serious questions about the discipline and readiness of South Korea's military, which faces North Korean troops across the world's most heavily fortified border. Confrontations between the rivals deepened recently following the North's nuclear test and long-range rocket launch.