The navies of South Korea and the United States have conducted a weekslong anti-submarine exercise in waters off the coast of Guam, the South's Navy said Sunday.

The biennial exercise, known as Silent Shark, which began on Oct. 6 and lasted until Sunday, is designed to enhance the countries' anti-submarine warfare proficiency against North Korean threats, according to the armed service.

South Korea earlier sent a 1,800-ton Son Won Il-class submarine and two P-3C patrol aircraft to participate in the drills, consisting of a joint search, track and attack exercise on a mock submarine.

The exercise comes at a time when Pyongyang has vowed to further strengthen its nuclear deterrence amid heightened tensions on the Korean Peninsula. Early last month, North Korea said it launched a new "tactical nuclear attack submarine" capable of carrying out an underwater nuclear attack. (Yonhap)