North Korea keeps up its missile barrage with launch of ICBM

Japan says North Korea has fired at least one more missile into the sea, bringing the day's total to at least four.

The launch on Thursday night came an hour after North Korea threatened to retaliate over a decision by the South Korean and US militaries to extend large-scale joint aerial exercises in response to the North's ramped up testing activity.

Japan's Prime Minister's Office says the missile is suspected to be ballistic but didn't immediately release flight details.

Earlier on Thursday, North Korea launched an ICBM and two-short range missiles into the sea, adding to a recent barrage of weapons tests. The ICBM triggered evacuation alerts and halted trains in northern Japan.