North Korea tried and failed to test-fire what appeared to be a medium-range Musudan missile on the birthday of founding leader Kim Il-Sung Friday, a high-profile misstep after Pyongyang claimed a series of breakthroughs in its nuclear weapons programme.

The missile disappeared from surveillance radar a few seconds after launch and is believed to have exploded midair, said a Seoul intelligence official quoted by Yonhap news agency.

There had been widespread intelligence reports in recent days that the North was preparing for the first-ever flight test of its Musudan missile, which is believed to be capable of striking US bases in the Pacific island of Guam.

The US and South Korean militaries both detected and tracked the early morning test.

"We assess that the launch failed," a US defence official said, adding that it was "presumably" a Musudan.

The April 15 birthday of Kim Il-Sung -- the grandfather of current ruler Kim Jong-Un -- is a major public holiday in North Korea, where key political anniversaries are often marked with displays of military muscle.

The country is also gearing up for a rare and much-hyped ruling party congress next month, at which Kim Jong-Un is expected to take credit for pushing the country's nuclear weapons programme to new heights.

Pyongyang has hailed a series of achievements in recent months, including miniaturising a nuclear warhead to fit on a missile, developing a warhead that can withstand atmospheric re-entry, and building a solid-fuel missile engine.

Last week, it said it had successfully tested an engine designed for an inter-continental ballistic missile (ICBM) that would "guarantee" an eventual nuclear strike on the US mainland.

Last Update: Wednesday, 20 May 2020 KSA 09:48 - GMT 06:48