UPDATED 4.57PM: A North Korean ballistic missile has failed shortly after launch - the second such test-fire flop in recent weeks but a clear show of defiance to the US and main ally China.

US and South Korean officials said the mid-range missile broke up minutes after taking off on Saturday morning from an area near Pukchang, just north of the capital, Pyongyang.

They said it reached an altitude of 71km before disintegrating, making it the North's fourth successive unsuccessful missile test since March.

President Donald Trump responded to the launch on Twitter: "North Korea disrespected the wishes of China & its highly respected President when it launched, though unsuccessfully, a missile today. Bad!"

Japan condemned the launch as absolutely unacceptable and a violation of UN resolutions.

There was no immediate reaction from China.

The test came as US Secretary of State Rex Tillerson warned the UN Security Council that failure to curb North Korea's nuclear and ballistic missile programs could lead to "catastrophic consequences".

The North has been conducting missile and nuclear weapons related activities at an unprecedented rate since the beginning of the year.

Tension had spiked on the Korean Peninsula over concern the North might conduct a long-range missile test, or its sixth nuclear test, about the time of the April 15 anniversary of its state founder's birth, or the day marking the founding of its military this week.

The timing of the launch suggested it was calculated to send a message as North Korea remained under the scrutiny of world powers, said Kim Dong-yub, of Kyungnam University's Institute of Far Eastern Studies in Seoul.

"It was planned at a complicated timing around the end of the South Korea-US joint military drills, the United States talking about military options and the announcement of North Korea policies and the Security Council meeting," Kim said.

South Korean and US forces have been conducting annual military drills since the beginning of March that conclude at the end of April.

Kim said North Korea might have obtained the data it wanted with the missile's short flight, then blown it up in the air.

Trump told Reuters on Thursday that North Korea was his biggest global challenge and a "major, major conflict" with it was possible over its nuclear and ballistic missile programs.

Trump praised Chinese leader Xi Jinping for "trying very hard" to rein it in.

In a show of force, the US is sending USS Carl Vinson aircraft carrier group to waters off the Korean peninsula, where it will join USS Michigan, a nuclear submarine that docked in South Korea on Tuesday.

The UN Security Council is likely to start discussing a statement to condemn the missile launch, diplomats say, but it was unlikely to be issued on Friday.