North Korea has fired a ballistic missile into the sea, South Korea's defence minister has said.
The launch was first reported by the Japanese coast guard early on Wednesday, before being confirmed by defence authorities in Seoul later.
The UN prohibits North Korea from ballistic and nuclear weapons tests.
This is the first missile launch by Pyongyang after leader Kim Jong-un pledged to bolster the country's defence capabilities last month.
"South Korean and US intelligence are closely analysing for further detail," the South's Joint Chiefs of Staff (JCS) said in a statement.
Japan's defence minister Nobuo Kishi said the ballistic missile had flown about 500 km (310 miles), Reuters reported.
According to one expert however, there was no way to confirm the full striking range of the missile.