North Korea has fired a missile into the sea off the east coast of the Korean Peninsula, South Korea's Joint Chiefs of Staff said on Thursday.
Japan's coast guard also said North Korea had fired what could be a ballistic missile.
The launch 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 criticized the recent series of joint military exercises between the U.S. and South Korea as escalating tension.