A suspected powerful mid-range North Korean missile crashed seconds after lift-off on Thursday, South Korea's Defence Ministry has said.
The incident is the second embarrassing failure in recent weeks.
South Korea's report of the North's failed launch is particularly humiliating as it comes ahead of a major ruling party meeting next week in Pyongyang, which leader Kim Jong Un is believed to be looking to as a way to put his stamp more forcefully on a government he inherited after his dictator father's death in late 2011.
A Defence Ministry official said the launch was likely to have been the second attempt for the inaugural test of a Musudan, a new, powerful mid-range missile which could one day be capable of reaching far-off US military bases in Asia and the Pacific.
The projectile crashed a few seconds after lift-off on Thursday.
The failed launch comes amid Pyongyang's anger over annual South Korean-US military drills that North Korea calls a rehearsal for an invasion. The North has in recent months fired many missiles and artillery shells into the sea in apparent protests against the drills.
Earlier this week, South Korean media reported that North Korea placed a Musudan missile on stand-by for an impending launch. Media reports said the missile on stand-by was one of the two Musudan missiles North Korea had earlier deployed in the north-east. One of them reportedly failed after being launched two weeks ago; the other on Thursday.
South Korean and US officials said there was a North Korean missile launch on April 15, the birthday of the North's late founder, but they have not officially confirmed it was a Musudan firing. US officials said the earlier launch ended in failure.
Musudan missiles have a potential range of about 2,180 miles (3,500km), which would put US military bases in Guam within their striking distance.
North Korea is also pushing to develop a nuclear-armed long-range missile capable of reaching the US mainland, but South Korea believes it does not yet possess such a missile.
Before this month's suspected launches, North Korea had never flight-tested a Musudan missile, though one was displayed during a military parade in 2010 in Pyongyang.
There is speculation in South Korea that North Korea will soon carry out a fifth nuclear test. The North conducted a fourth atomic test in January and a long-range rocket launch in February, earning worldwide condemnation and tougher UN sanctions.
South Korean President Park Geun-hye said on Thursday that there were unspecified signs that a fifth test was "imminent".
She warned that another nuclear test would result in North Korea suffering harsher sanctions.