South Korea, the United States and Japan conducted a joint missile defense exercise in international waters south of the Korean Peninsula on Tuesday in response to North Korea’s failed launch of a spy satellite last week.

The exercise took place the same day that Pyongyang’s state media reported that leader Kim Jong-un had denounced growing military cooperation between Seoul, Washington and Tokyo during a visit to his regime’s naval command on Monday to mark Navy Day in the North.

According to South Korean officials, the trilateral missile defense exercise took place south of Jeju Island and featured the Aegis-equipped destroyers ROKS Yulgok Yi I, USS Benfold and JS Haguro, according to the South Korean Navy.

The Aegis combat system is a U.S.-developed integrated naval weapons system that uses computers and radars to track and guide weapons to destroy enemy targets.

The South Korean Navy said the allies undertook the exercise in response to the advancing threat posed by the North’s missile and nuclear weapons programs.

The exercise is the third trilateral missile defense exercise to take place this year and the fourth since President Yoon Suk Yeol took office in May last year.

The Navy also described Pyongyang’s failed attempt to launch a satellite last week as a “clear” violation of successive United Nations Security Council resolutions, which bar the North from conducting any tests involving ballistic missile technology.

The joint exercise by the United States and its East Asian allies focused on launch detection, missile tracking and sharing information using a computer-simulated target, according to the Navy.

The three countries’ militaries are currently working to operationalize a system to share real-time information on North Korean missiles before the end of this year, as was agreed by South Korean President Yoon Suk Yeol, U.S. President Joe Biden and Japanese Prime Minister Fumio Kishida at their summit at Camp David earlier this month.

The three leaders also committed to enhance their security and economic cooperation and carry out trilateral exercises regularly.

North Korean leader Kim Jong-un greets North Korean navy officers at the regime’s naval headquarters in Pyongsong, South Pyongan Province, in this photograph release by the state-controlled Korean Central News Agency. His daughter Kim Ju-ae stands to the left. [YONHAP]

The North’s state media reported that leader Kim compared the three leaders to “gang bosses” for conducting joint exercises during his visit to the regime’s naval command in Pyongsong, South Pyongan Province, on Monday.

Kim also claimed the three countries are driving up the “danger of a nuclear war” in the seas surrounding the Korean Peninsula, according to the state-controlled Korean Central News Agency (KCNA).

Kim cited “the enemies’ recent aggressive attempts and the nature of [their] military actions” as justification for the North to “rapidly develop” it naval forces.

With its eastern and western coasts separated by the presence of South Korea, the two main fleets of the North Korean Navy on either side face significant geographical and operational challenges supporting each other should armed hostilities break out on the peninsula.

While most of the North’s naval assets are believed to be obsolete or limited in range, the KCNA quoted Kim as saying that his regime would strengthen its navy to make it an “all-round and powerful” force during his observation of cruise missile launches from a new Amnok-class naval corvette last week.

Kim reiterated that vow during his visit on Monday, where he said the North’s navy must “put all its effort into finalizing its war readiness to maintain the constant combat alertness, as well as to prepare to break the enemy’s will for war in contingencies and carry out the military strategy of the Supreme Headquarters.”

Other naval assets developed by the North in recent years include a Sinpo-C-class ballistic missile-armed submarine with stealthy air-independent propulsion, whose construction was reported by South Korean intelligence in August 2020.

The visit by Kim to the naval command’s headquarters on Monday was his first since the regime began celebrating Aug. 28 as Navy Day in 2014.

Photographs of the North Korean leader’s visit to the naval command showed he was accompanied by his daughter, Kim Ju-ae, marking her first public appearance in three months.

Kim’s daughter was last photographed by state media when she accompanied her father on his inspection of preparations for the North’s first attempted launch of a spy satellite in May.

BY MICHAEL LEE [lee.junhyuk@joongang.co.kr]