The latest launch is seen by analysts as the most provocative test by North Korea since it started the talks with the United States in 2018.
North Korea said on Thursday it had successfully test-fired a new type of submarine-launched ballistic missile (SLBM) from the sea off its east coast on Wednesday, aimed at containing external threats and bolstering its self-defence.
The launch came a day after it announced the resumption of talks with the United States on ending its nuclear programme. It is seen by analysts as the most provocative test by North Korea since it started the talks with the United States in 2018.
The new type of SLBM called Pukguksong-3 was "fired in vertical mode," the North's official KCNA news agency said, confirming an assessment by South Korea's military on Wednesday that the missile was launched at a lofted angle.
"The successful new-type SLBM test-firing comes to be of great significance as it ushered in a new phase in containing the outside forces' threat to the DPRK and further bolstering its military muscle for self-defence," KCNA said.
DPRK is short for the North's official name, the Democratic People's Republic of Korea.
The test "had no adverse impact on the security of neighboring countries," KCNA said.
Photos of the launch in the official newspaper Rodong Sinmun showed a black-and-white painted missile emerging from the water and flying into the grey sky.
North Korean leader Kim Jong-un "sent warm congratulations" to those who had carried out the successful test-firing, KCNA said, indicating that Kim was not at the site.