North Korea has fired its most advanced long-range missile, defying UN warnings.
Last week, South Korean and US defence officials met last week to update plans on how to respond to a nuclear attack from the North.
North Korea had said in response it would take „more offensive countermeasures”.
The isolated state launched the long-range missile on Monday morning about 08:24 local time (23:24 Sunday GMT) from the Pyongyang area.
ICBMs have the range to reach the North American continent. Such missiles can be fired with less warning, as they do not need to be fuelled prior to launch.
Monday’s launch is North Korea’s fifth successful launch of an ICBM this year.
Last week, South Korea’s national security advisor Kim Tae-hyo said he was expecting the North to launch an ICBM at some point in December.
North Korea is also working to develop a new solid-fuel medium-range ballistic missile. Last month it claimed to have successfully tested the engine, but the missile had not yet been successfully launched.
As North Korea continues to refine and add to its arsenal of nuclear weapons, South Korea and the United States are stepping up their defence of the region.
In a meeting in Washington on Friday, officials updated their contingency plans for how to respond to a North Korean nuclear attack. The two countries also agreed to war-game the use of nuclear weapons in their military exercises next summer.