Joint Chiefs of Staff Chairman Adm. Kim Myung-soo visits a monument, built in remembrance of 46 sailors who were killed during the 2010 sinking of the Cheonan corvette, at the Navy's 2nd Fleet Command in Pyeongtaek, 60 kilometers south of Seoul, on Jan. 17, in this photo provided by his office. Yonhap

South Korea's top military officer on Friday visited the Navy's 2nd Fleet Command and a radar site under the command to inspect its readiness posture against North Korean threats near the western inter-Korean maritime border, the Joint Chiefs of Staff (JCS) said.

JCS Chairman Adm. Kim Myung-soo visited the naval command in Pyeongtaek, 60 kilometers south of Seoul, where he paid respects at a monument built in remembrance of 46 sailors who were killed during the 2010 sinking of the Cheonan corvette by a North Korean torpedo attack in the Yellow Sea, his office said.

Kim also paid tribute at a monument commemorating the South's victory in inter-Korean naval skirmishes that took place off the border island of Yeonpyeong in 1999 and 2002, respectively.

As part of the visit, the JCS chairman inspected surveillance operations at a naval radar site on the western island of Eocheong, emphasizing that the unit is the "front line" defending the rear and side maritime gateways to the greater Seoul area.

"The Northern Limit Line (NLL) is a maritime border that our comrades ahead of us have defended for more than 70 years with their lives and it has always been a site of North Korea's deceptive and abrupt provocations," Kim said. "Prepare to show our determination through action."

Waters near the NLL have been a flashpoint between the two Koreas, with the North never recognizing the border and demanding that it be re-drawn further south. (Yonhap)