The device was described as a "surface-to-surface medium-to-long-range ballistic missile", the Korean state news agency KCNA reported.
South Korea's defence ministry called it an armed provocation to test the response of US President Donald Trump.
North Korea's latest ballistic missile test has been widely condemned.
KCNA reported that the test of the Pukguksong-2 missile, a new type of strategic weapon said to be capable of carrying a nuclear warhead, was supervised by leader Kim Jong-un.