Kim Jong-un-led North Korea test-fired a ballistic missile farther than ever before on Tuesday, sending it soaring over Japan for the first time in five years and prompting a warning for residents there to take shelter.

The United States and South Korea in response launched four missiles off the east coast of the Korean Peninsula on Wednesday morning local time, according to South Korea’s Joint Chiefs of Staff.

The test was the allies’ second exercise in under 24 hours, following the provocative test-launch by neighboring North Korea, which fired a missile without warning over Japan in a significant escalation of its weapons testing program.

Flying missiles over or towards other countries without consultation or warning contradicts international norms. Most countries refrain from doing it as it can be mistakenly construed as an attack.

People in North Japan, including Aomori City and Hokkaido Island, woke up to text alerts and siren noises. The alerts read that North Korea had launched a missile and asked people to evacuate underground or into buildings. As the missile flew above, the people were asked to watch out for falling debris. The missile flew higher than the ISS (International Space Station), reaching a height of 1,000km, and travelled the longest ever distance as a North Korean missile.

North Korea accuses the United States and its allies of threatening it with exercises and defence build-ups.

Recent tests had drawn relatively muted responses from Washington, which is focused on the war in Ukraine as well as other domestic and foreign crises.

UN resolutions prohibit North Korea from testing any kind of ballistic missile. However, Tuesday's missile launch was the fifth such test in 10 days.