North Korea has fired a ballistic missile in defiance of calls to rein in its weapons program, South Korean and US officials said, days after a new leader took office in the South, pledging to engage it in dialogue.
The US Pacific Command said it was assessing the type of missile but it was "not consistent with an intercontinental ballistic missile".
Japanese Defence Minister Tomomi Inada said the missile could be of a new type.
The missile flew 700 km and reached an altitude of more than 2000 km, according to officials in South Korea and Japan, further and higher than an intermediate-range missile North Korea successfully tested in February from the same region of Kusong, northwest of its capital, Pyongyang.
North Korea is widely believed to be developing an intercontinental missile tipped with a nuclear weapon that is capable of reaching the United States. US President Donald Trump has vowed not to let that happen.
Experts said Sunday's test showed a considerably longer range than missiles North Korea had previously tested, meaning it had likely made improvements since its February test.
The reported altitude would indicate the missile was launched at a high trajectory.
David Wright, co-director of the UCS Global Security Program and a missile expert, said if the missile had been fired at a standard trajectory, it would have had a maximum range of about 4500 km
Kim Dong-yub, Kyungnam University's Institute of Far Eastern Studies in Seoul, said he estimated a standard trajectory firing would give it a range of 6000 km, meaning it would be capable of reaching Hawaii.
An intercontinental ballistic missile is considered to have a range of more than 6000 km.
Japan said the missile flew for 30 minutes before dropping into the sea between North Korea's east coast and Japan. The North has consistently test-fired missiles in that direction.
"If that report ... is correct, then the launch may indeed represent a new missile with a long range," said Jonathan McDowell of the Harvard Smithsonian Center for Astrophysics, referring the estimated altitude of more than 2,000 km.
"It is definitely concerning," McDowell said.
In Washington, the White House said Trump "cannot imagine Russia is pleased" with the test as the missile landed closer to Russia than to Japan.
"With the missile impacting so close to Russian soil - in fact, closer to Russia than to Japan - the President cannot imagine that Russia is pleased," it said.
The launch served as a call for all nations to implement stronger sanctions against North Korea, it added.
The launch, at 5.27 am Seoul time on Sunday, came two weeks after North Korea fired a missile that disintegrated minutes into flight, marking its fourth consecutive failure since March.
South Korean President Moon Jae-in, who took office on Wednesday, held his first National Security Council in response to the launch, which he called a "clear violation" of UN Security Council resolutions, his office said.
"The president said while South Korea remains open to the possibility of dialogue with North Korea, it is only possible when the North shows a change in attitude," Yoon Young-chan, Moon's press secretary, told a briefing.
Moon won Tuesday's election on a platform of a moderate approach to North Korea and has said he would be willing to go to Pyongyang under the right circumstances, arguing dialogue must be used in parallel with sanctions.
China, the North's sole main ally which nevertheless objects to its weapons programs, called for restraint and for no one to exacerbate tension.
