North Korea has conducted what is thought to be its biggest missile launch since 2017.
South Korea reported that the launch took place at 07:52 local time on Sunday (22:52 GMT) off North Korea’s east coast.
Japan, South Korea and the US have all condemned the launch, the seventh test this month.
The UN prohibits North Korea from ballistic and nuclear weapons tests, and has imposed strict sanctions.
But the East Asian state regularly defies the ban, and leader Kim Jong-un has vowed to bolster his country’s defences.
South Korea’s National Security Council said Sunday’s test was an intermediate-range ballistic missile (IRBM), which would be the biggest missile tested since November 2017.
Japanese and South Korean officials estimated that the missile reached an altitude of 2,000km (1240 miles) and flew for 30 minutes to a distance of 800km (500 miles). It landed in the Sea of Japan.
January was already one of the busiest months on record for North Korea’s missile programme, with several short range missiles fired into the sea.
The US said the tests violated UN resolutions and called on North Korea to refrain from provocations and to engage in substantive dialogue.
South Korea’s president, Moon Jae-in, said the latest flurry of missile tests was reminiscent of the heightened tensions in 2017, when North Korea conducted several nuclear tests and launched its largest missiles, including some that flew over Japan.
In an address before New Year, Mr Kim called for the military to be strengthened with cutting-edge technology.
Since then, several different types of weapon have reportedly been tested using a range of launch locations.
In 2018, Mr Kim announced a moratorium on testing nuclear weapons or its longest range intercontinental ballistic missiles (ICBMs).
But the North Korean leader said in 2019 he is no longer bound by the moratorium.
The US imposed more sanctions on North Korea earlier in January, in response to previous missile launches. Talks between the two countries have stalled since US President Joe Biden took office.