USS Kentucky (SSBN-737), an Ohio-class nuclear ballistic missile submarine, made the first visit by a U.S. submarine to Busan, South Korea in 40 years.
The visit was part of the Washington Declaration, a pact between the U.S. and South Korea to strengthen their alliance and enhance deterrence capabilities.
It is the first time a U.S. ballistic nuclear submarine has visited South Korea since the 1980s, highlighting the commitment to extended deterrence against North Korea.
USS Kentucky is based in Naval Base Kitsap, Bangor, Washington.
The submarine is equipped with Trident II D5 intercontinental ballistic missiles and is one of 14 submarines in the U.S. fleet.
USS Michigan, another Ohio-class submarine, visited Busan last month, but it has been converted to carry Tomahawk Land Attack Missiles instead of nuclear ballistic missiles.
The visit of USS Kentucky to Busan occurred shortly after North Korea launched an intercontinental ballistic missile, drawing protests from the U.S., United Nations, and Japan.
Japan's Office of the Prime Minister tweeted about North Korea's suspected ICBM launch on the same day.