North Korea has fired a missile into the sea off the east coast of the Korean Peninsula, South Korea's Joint Chiefs of Staff says.
Japan's coast guard also said North Korea had fired what could be a ballistic missile.
The launch on Thursday comes two days after North Korean state media KCNA reported that leader Kim Jong-un called for strengthening the country's war deterrence in a "more practical and offensive" manner to counter what it called moves of aggression by the United States.
North Korea has criticised the recent series of joint military exercises between the US and South Korea as escalating tension.