South Korea's military says Pyongyang has fired a ballistic missile toward its eastern waters. The launch comes four days after the leaders of the United States, Japan and South Korea held a trilateral summit.

South Korea's Joint Chiefs of Staff say North Korea launched a short-range ballistic missile from the eastern city of Wonsan on 10:48 a.m. on Thursday.

Japan's Defense Ministry also confirmed the launch shortly after midday. It says the missile landed in waters to the east of the Korean Peninsula.

North Korea has been firing missiles at an unprecedented rate. The country launched a ballistic missile on Wednesday last week. It fell into the Sea of Japan, outside Japan's exclusive economic zone.

Two weeks ago, the North launched three missiles. They included what appeared to be an intercontinental ballistic missile.

About one hour before the latest launch, North Korean Foreign Minister Choe Son Hui released a statement condemning the summit between Japan, the US and South Korea in the Cambodian capital of Phnom Penh.

She said Sunday's talks would bring the situation on the Korean Peninsula to "an unpredictable phase."

And she warned that the more the US strengthens its "extended deterrence" to its allies and intensifies "provocative and bluffing" military activities, the fiercer North Korea's military response will be.

Observers believe Thursday's launch is a reaction to the three nations' pledge to cooperate in strengthening their deterrence against the North.