North Korea launches ballistic missile toward sea, South Korea says

North Korea launched a ballistic missile toward the sea on Thursday, South Korea's military said, days after North Korean leader Kim Jong Un vowed to enhance his nuclear arsenal in more "practical and offensive" ways.

South Korea's Joint Chiefs of Staff said the launch occurred on Thursday morning but gave no further details, such as how far the missile flew and exactly what weapon the North fired.

Japan's prime minister's office warned residents in its northernmost main island of Hokkaido to immediately seek shelter inside sturdy buildings or underground. It said the North Korean missile was expected to land near Hokkaido at around 8 a.m. (23:00 GMT).