North Korea made a failed launch of a medium-range ballistic missile Thursday, according to South Korean military sources cited by Yonhap news agency.
The rocket fired from the country's east coast crashed "a few seconds" after being launched, the sources said.
The test may have involved a mid-range Musudan missile, which Pyongyang has tested before and which can reach a distance of 3,000-4,000 kilometres.
The launch was observed by US reconnaissance satellites, Yonhap reported.
Pyongyang had tried to launch the same type of rocket earlier in April, but it exploded shortly after being fired, Yonhap said.
On Saturday, North Korea claimed to have successfully fired a ballistic missile from a submarine, but Seoul countered that it had only stayed in the air for 30 kilometres.
South Korea fears its isolated Stalinist neighbour to the north will carry out another nuclear weapons test ahead of its first party congress since 1980, due to take place on May 6, as a show of strength.
North Korea is forbidden from launching ballistic missiles under UN sanctions.
Tensions are high on the Korean peninsula, as Pyongyang and Seoul exchange accusations over the North's nuclear and missile tests since January, the resulting international sanctions, and the South's annual military manoeuvres with the United States.