Kim urges vigilance after defection

North Korean leader Kim Jong-un urged vigilance from the State Security Ministry, the official Korean Central News Agency reported, the same day a soldier shot two officers and defected to the South.

"The Ministry of State Security has a very important duty to perform to protect the sovereignty of the country and the nation," KCNA quoted Kim as saying on Saturday while viewing a statue of his late father at the ministry.

A North Korean soldier fled across the demilitarised zone around noon after shooting his platoon and squad leaders, South Korea's Defence Ministry said.

Kim became head of the totalitarian state in December after the death of his father Kim Jong-il, who ruled the secretive nation from 1994 to 2011. He took the country's top rank of marshal in July, the final step to secure his power as leader of the impoverished nation's 1.2-million-strong armed forces.

The promotion came days after Kim Jong-un fired veteran army chief Ri Yong-ho, in the biggest publicly revealed power shift since his succession.

"The security men should wage a fierce struggle against the enemies," KCNA quoted Kim as saying. He also called for incorporating modern information technology into state security, the report said. KCNA did not mention the defection.