The South Korean Navy carried out a firing exercise off the country's east coast Friday to strengthen its capability against a possible invasion by North Korean submarines, officers here said.

Flatly rejecting Japan's call a day earlier to cancel the drill, the Navy held the one-day exercise in the East Sea, some 50 kilometers away from the country's eastern port of Jukbyeon, North Gyeongsang Province, as scheduled.

On Wednesday, Tokyo urged Seoul to cancel the exercise, claiming that the venue includes part of its territorial waters near Dokdo. It was the latest in a series of Tokyo's renewed attempts to lay claims to South Korea's easternmost islets.

Though the Navy has held the drill on a regular basis, it marks the first time that the military made it public.

"The unusual move was due in part to the recent naval threat by North Korea," a Navy officer said, requesting anonymity.  

Earlier this week, North Korean leader Kim Jong-un visited its naval unit in the East Sea and guided a drill aboard its largest submarine, stressing the need to raise combat preparations and underwater operation capability.

Friday's exercise was based upon the scenario where the South Korean Navy detects, chases and destroys a North Korean submarine that invades the South's waters.

Mobilizing 19 naval ships, including a 3,200-ton KDX-I light destroyer ship, called the King Gwanggaeto, two P-3CK anti-submarine surveillance aircraft and a Lynx antisubmarine helicopter, the Navy fired its homegrown torpedo named the Cheongsangeo, or Blue Shark; a ship-to-ship cruise missile named Haeseong, or Sea Star; and an air-to-ground missile named Harpoon into the sea, the Navy noted.

Adm. Hwang Ki-chul, the chief of the Naval Operations, who conducted the drill, ordered its officers to pursue, if provoked, the enemy's submarines "to the end and bury them at sea," according to the Navy.

Noting that the torpedo and cruise missile successfully hit the target, the Navy said it will further strengthen its readiness posture "with a firm resolution to turn the East Sea into a grave of the North's submarines." (Yonhap)