South Korea's Navy chief on Monday inspected a military exercise in the East Sea designed to enhance its capabilities to counter North Korea's submarine-launched ballistic missiles.

Chief of Naval Operations Adm. Um Hyun-seong called for full readiness and a swift reaction if provoked during the inspection aboard a P-3 maritime patrol aircraft, widely known as a "submarine killer."

The exercise began Thursday with the aim to assess and improve South Korea's capabilities to strike North Korean submarines and intercept its missiles, the Navy said in a statement. It runs until Tuesday.

It involves 10 warships, such as the 7,600-ton Aegis-equipped Sejong the Great destroyer, submarines, P-3 maritime patrol aircraft and fighter jets, the Navy said.

Um called on the naval forces to stay on high alert and respond swiftly and resolutely to any provocative acts by the communist country.

"North Korea is bent on developing nuclear weapons and submarine-launched ballistic missiles. It may provoke with those lethal weapons at any time. The drills to counter (the North's) submarines are essential to protecting our marine routes and warships from the enemy's attacks," a Navy official said.

During the drill, officials from the US Undersea Warfighting Development Center (UWDC) assess South Korean forces' operations against submarines, warships and aircraft sent by the communist North, the Navy said in a statement

In 2015, Washington agreed to support Seoul's efforts to bolster its capabilities to detect, trace and attack North Korean submarines in the event of any signs of a conflict on the Korean Peninsula, it said.

Starting in 2017, the two countries' naval forces plan to conduct a joint assessment of the Korean Navy's anti-submarine capabilities, it added.

This year alone, Pyongyang has conducted two underground nuclear tests and fired off some two dozen ballistic missiles. Such developments have escalated concerns that the North is approaching its stated goal of developing a nuclear-tipped long-range ballistic missile that can hit parts of the US mainland.  (Yonhap)