North Korea attempted to fire a missile from its east coast early on Tuesday morning but the launch appears to have failed, say South Korean military officials.
Tension in Northeast Asia has been high since North Korea conducted its fourth nuclear test in January and followed that with a satellite launch and test launches of various missiles.
A South Korean news agency said it appeared North Korea had attempted to launch an intermediate-range Musudan missile. North Korea attempted three test launches of the Musudan in April, all of which failed.
North Korea has never had a successful launch of the Musudan, which theoretically has the range to reach any part of Japan and the US territory of Guam.
The attempted launch took place near the east coast city of Wonson, the same area where previous Musudan tests had taken place.
The weapons technology tests this year were in the run-up to the first congress in 36 years of North Korea's ruling Worker's Party. Tuesday's attempted launch appears to have been its first missile test since then.