North Korea has test-launched a ballistic missile that landed in the Sea of Japan, the South Korean, Japanese and US militaries say.
The launch on Sunday is a direct challenge to the new South Korean president elected four days ago and comes as US, Japanese and European navies gather for joint war games in the Pacific.
It wasn't immediately clear what type of ballistic missile was launched, although the US Pacific Command said that "the flight is not consistent with an intercontinental ballistic missile".
Outside militaries will closely analyse what the North fired. While Pyongyang regularly tests shorter-range missiles, it is also working to master the technology needed to field nuclear-tipped missiles that can reach the US mainland. Past North Korean missiles have flown farther than Sunday's test, landing closer to Japan, but this launch follows a series of high-profile failures.
Whatever the type of missile, the launch forces the new South Korean leader, Moon Jae-in, to put dealing with Pyongyang, at least for now, above the domestic economic agenda he'd made a priority during his early days in office.
Mr Jae-in, a liberal who favours a softer approach to the North than his conservative predecessors, strongly condemned the launch during an emergency national security meeting, calling it a clear violation of UN Security Council resolutions and a serious challenge to international peace and security, according to senior presidential secretary Yoon Young-chan.
"The president expressed deep regret over the fact that this provocation occurred just days after a new government was launched in South Korea," Mr Young-chan told a televised conference. "The president said we are leaving open the possibility of dialogue with North Korea, but we should sternly deal with a provocation to prevent North Korea from miscalculating."
Japanese Chief Cabinet Secretary Yoshihide Suga said the missile flew about 800km from a launch site on North Korea's western coast for about 30 minutes and landed in the Sea of Japan, but not inside Japan's exclusive economic zone.
Japan's Defense Ministry says the missile likely reached an altitude of 2000km. Prime Minister Shinzo Abe told reporters the launch is "absolutely unacceptable" and Japan will respond resolutely.
South Korea's Joint Chiefs of Staff said in a statement that the missile was fired early on Sunday morning from near Kusong, in North Phyongan province.
North Korea's past satellite rocket launches have been called clandestine tests of ICBM technology, but it is not believed to have tested a true intercontinental ballistic missile yet. The Trump administration has called North Korean ballistic and nuclear efforts unacceptable and has swung between threats of military action and offers to talk as it formulates a policy.
The North's state media said on Saturday the nation will bolster its nuclear capability unless the US abandons its hostile policy.