North Korea has fired a missile, but it appears to have failed, South Korean military officials say.
The missile launched was believed to be an intermediate-range Musudan missile.
The US military said it has also detected a missile launch from North Korea.
Japan has put its military on alert for a possible missile launch and South Korea's Yonhap News Agency said the North was seen moving an intermediate-range missile to its east coast.
North Korea has failed in all four previous attempts to launch the Musudan, which theoretically has the range to reach any part of Japan and Guam.