North Korea has fired a submarine-launched ballistic missile into waters off the coast of Japan, South Korea's military has said.
The launch comes weeks after South Korea unveiled its own such weapon.
Pyongyang unveiled a "new" type of submarine-launched missile in January, describing it as "the world's most powerful weapon".
It comes as South Korea, Japan and US intelligence chiefs reportedly meet in Seoul to discuss North Korea.
In recent weeks, Pyongyang has embarked on a flurry of tests of what it claims to be hypersonic and long-range cruise missiles, and anti-aircraft weapons.
Some of these tests violate strict international sanctions.
North Korea is specifically prohibited by the United Nations from testing ballistic missiles as well as nuclear weapons.
On Tuesday South Korea's Joint Chiefs of Staff said one missile was launched from the port of Sinpo, in the east of North Korea where Pyongyang usually bases its submarines. It landed in the East Sea, also known as the Sea of Japan.
South Korean media reported that this particular missile is believed to have travelled between 430 and 450km at an apogee - or maximum height - of 60km.
It is unclear if the missile was launched from a submarine or from an underwater platform.
Japan's Prime Minister Fumio Kishida said there were two ballistic missiles fired, calling the launches "very regrettable".
Why is 'submarine-capable' significant?
In October 2019 North Korea tested a submarine-launched ballistic missile, firing a Pukguksong-3 from an underwater platform.
At the time, state news agency KCNA said it was fired at a high angle to "contain external threat".
If the missile had been launched on a standard trajectory, instead of a vertical one, it could have travelled around 1,900 km (1,200 miles). That would have put all of South Korea and Japan within range.
Being launched from a submarine can also make missiles harder to detect, and allows them to get closer to other targets.
BDST: 1252 HRS, OCT 19, 2021