North Korea test-fires ballistic missile (Photo: AFP/VNA)

South Korea's Joint Chiefs of Staff said South Korea raised its surveillance posture and is maintaining military readiness in close coordination with the US.

The missile launch came after North Korean warplanes flew close to North Korea’s border. The South Korean Air Force deployed F-35 stealth fighters and other military equipment to the scene, the Joint Chiefs said.

North Korea claimed its latest ballistic missile launch was a response to what it called the South Korean military's "provocative action". 

The UN condemned North Korea’s latest launch, saying it violated Security Council resolutions, and threatens peace and stability in the region.

It was North Korea's eighth missile launch in less than three weeks.