North Korea fired a submarine-launched ballistic missile off its east coast on Tuesday, setting off alarm bells across the region.
The launch was reported by military officials in South Korea and Japan, and comes just after South Korean envoys met with U.S. officials to discuss the nuclear standoff on Monday.
Pyongyang has ramped up its military activity dramatically in recent weeks, and Tuesday's launch marks its latest missile test.
The missile was launched shortly after 10 a.m. local time from the sea in the vicinity of Sinpo, South Korea's Joint Chiefs of Staff said,where North Korea keeps submarines as well as equipment for test firing missiles.
It wasn't clear if it was fired from a submarine or from a test barge.
News of the launch quickly overshadowed a major arms fair taking place in Seoul, and pulled Japanese Prime Minister Fumio Kishida away from several scheduled events.
Kishida called the missile tests "regrettable" while South Korea's national security council called an emergency meeting, and urged Pyongyang to return to the negotiating table.
In a statement, the U.S. military called Tuesday's launch "destabilizing," but said it did not pose an immediate threat.
Analysts suggest Pyongyang's latest tests aim to match or surpass South Korea's own quietly expanding arsenal.
Pyongyang has decried what it calls double standards by Seoul and Washington as it faces international sanctions over its weapons program.