The missile lifted off at 5:30 a.m. but deviated from a "normal" trajectory, a JCS official told reporters.

South Korea and the United States concluded the launch failed after their joint assessment, he added without elaborating further.

It was North Korea's first test-launch of a Musudan missile, which the North is believed to have deployed against South Korea and other countries in recent years. The North may have deployed some 50 Musudan missiles.

The South Korean military had previously detected North Korea deploying one or two Musudan missiles near the east coastal city of Wonsan in the previous weeks for a potential launch.

With a range of 3,000-4,000 kilometers, the missile can fly over South Korea and Japan to reach as far as Guam, where the United States military forces are stationed.

North Korea is prohibited by a series of United Nations Security Council resolutions from launching ballistic missiles.

The latest launch is apparently part of North Korea's celebration of the 104th birthday of the country's founding father Kim Il-sung. The country has marked the national holiday in the past with elaborate military events.

South Korea's military said it is bracing for further military provocations by North Korea as Pyongyang is moving toward more large-scale events down the road, including its ruling party's 7th congress set for early May.

"We are preparing against the possibility that the North could carry out heavyweight provocations at any time, including the fifth nuclear test," a military official said.

The latest defiant military action followed the UNSC's adoption of a biting resolution on North Korea in early March in response to the communist country's fourth nuclear test in January and a long-range rocket launch in February.

Since the new resolution, North Korea protested with a test-firing of a series of short and mid-range missile and multiple rocket launchers, heightening military tension on the Korean Peninsula. (Yonhap)