A high-ranking North Korean Army official was reportedly executed with a mortar round for drinking liquor during the 100-day mourning period after Kim Jong-il's death, South Korean media reported on Thursday.

According to the Chosun Ilbo daily, General Kim Chol, who served as vice minister of the Army, was executed by a firing squad in January on the order to leave "no trace of him behind, down to his hair" given by Kim Jong-un, who took over as head of state after the death of his father in December 2011.

The newspaper quoted a South Korean government source as saying that Kim Jong-un ordered loyal officials to "get rid of" anyone caught misbehaving during the mourning period for his father.

Besides the assistant chief and an assistant chief of the General Staff Department, frontline commanders were also executed, the source said.

Kim Jong-il also purged dissenters, even those caught for minor infractions, after the death of his father Kim Il-sung in 1994, the South Korean daily said.