South Korea's top military officer called Wednesday for a watertight readiness against possible provocations by North Korea, the Joint Chiefs of Staff said.

The JCS chairman, Adm. Choi Yun-hee, made the remarks while visiting a front-line Army unit in Hwacheon, Gangwon Province, two days after a North Korean soldier defected to the South after crossing the military demarcation line in the region.

"It is necessary to make every effort to maintain full readiness by effectively managing guard troops and border defense equipment," he told the service personnel, noting the high probability "of North Koreans' border intrusions or defections through the region by making use of the thick woods and heavy fog."

Public criticism has mounted over the latest defection case, as the 19-year-old North Korean private was found to have stayed overnight near a South Korean guard post inside the Demilitarized Zone before being caught.

The chairman also urged the troops to respond to any provocations by the communist country "in a swift, precise and perfect fashion," pointing to high possibilities for the bellicose regime to launch "surprise attacks."

"North Korea has heightened tensions near the border areas and the Northern Limit Line to break through unfavorable internal and external conditions," Choi stated.

According to the JCS data, North Korean patrol boats have crossed the NLL, the de facto inter-Korean sea border in the Yellow Sea, four times this month alone.

With an aim to prevent defections of its soldiers, Pyongyang has also taken diverse measures, such as beefing up patrols along the inter-Korean border, burying land mines and checking to see if border markers are properly set up. (Yonhap)