South Korea’s Joint Chiefs of Staff said the launch on Saturday occurred from waters near the eastern port city of Sinpo, where North Korea has a major shipyard building submarines, however, they did not immediately say how far the missile flew.
It also wasn’t clear whether the launch may have involved an actual submarine or an underwater test platform.
Japan’s Defense Ministry also confirmed the launch, but did not release flight details.
Japanese Prime Minister Fumio Kishida ordered officials to prepare for all “unforeseeable situations” and secure the safety of aircraft and ships, but there were no immediate reports of damages.
The launch was apparently North Korea’s first demonstration of a submarine-fired ballistic system since October last year when it test-launched a new short-range missile from the 8.24 Yongung – its only known submarine capable of firing a missile – in what was its first underwater test launch since 2019.
The latest launch was likely North Korea’s 15th round of missile firings this year, including its first test of an intercontinental ballistic missile since 2017 in March that demonstrated potential range to reach the entirety of the US mainland.
The launch came three days after the South Korean and Japanese militaries detected the North firing a suspected ballistic missile from near its capital, Pyongyang, on Wednesday.
The South Korean and Japanese militaries said the North Korean missile fired on Wednesday traveled about 500 kilometers (310 miles) at a maximum altitude of 800 kilometers (500 miles). North Korean state media has yet to comment on that test.