It is the first time in nearly six years that a submarine classified as “SSGN” by the US Navy, or a cruise-missile submarine, has stopped off in South Korea.

The arrival comes after North Korea fired two short-range missiles off its east coast on Thursday and follows a failed attempt by Pyongyang to launch a spy satellite last month.

In April, South Korean president Yoon Suk-yeol and US president Joe Biden agreed in Washington to “further enhance the regular visibility of strategic assets” on the Korean Peninsula.

The leaders also agreed that a U.S. Navy nuclear-armed ballistic missile submarine (SSBN) will visit South Korea for the first time since the 1980s to help demonstrate Washington’s resolve to protect the country from a North Korean attack. There was no timetable given for such a visit.