North Korea on Saturday launched a ballistic missile that blew up over land, a spokesman for the US Pacific Command said.

The missile didn't leave North Korean territory, CNN quoted US Navy Commander Dave Benham as saying.

A US military assessment found the main part of the missile landed approximately 35 kilometres (22 miles) from Pukchang airfield, a US official told media.

" North Korea disrespected the wishes of China & its highly respected President when it launched, though unsuccessfully, a missile today. Bad!," US President Donald Trump tweeted.

South Korean officials said the test likely was a failure.

"We are analysing additional information," the nation's Joint Chiefs of Staff said in a statement. "Our military is maintaining a thorough defence posture while keeping a close eye on the possibility of North Korea's further provocations."
  

White House officials said Trump was briefed as Air Force One returned to Maryland from Atlanta, where Trump earlier addressed a meeting of the National Rifle Association.

The test-fired missile probably was a medium-range ballistic missile called a KN-17, the US official said. The KN-17 is a land-based solid-fuel missile fired from a mobile launcher.

North Korean state media did not report on Saturday's launch, as is customary in the case of an unsuccessful test.