SEOUL, June 16 (Reuters) - A U.S. nuclear-powered submarine has arrived at a port in the South Korean city of Busan, the South Korean military said on Friday.

It is the first time in nearly six years that a submarine classified as "SSGN" by the U.S. 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 U.S. 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.