North Korea launched a new missile this week called the Hwasong-15 missile - a new type of device experts say is capable of hitting Washington.
South Korea responded swiftly by firing missiles, six minutes later, into the waters off eastern Korea to demonstrate Seoul’s readiness for war.
But, security analysts say South Korea may not be able to respond as swiftly or accurately in a real wartime scenario.
Yang Uk, a senior defence researcher at Seoul think tank, the Korea Defense and Security Forum, said: “What we saw Wednesday was an active response to a North Korean missile launch that South Korea calls its ‘kill chain’ system.”
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The kill chain is part of a larger defence system designed to pre-emptively strike the North’s missile system during a nuclear attack.
But, a retired senior South Korean official said the South lacks a military satellite that can watch the North.
However, the US and Japanese satellites share images with South Korean officials in real time.
The recent missile was launched from Pyongsong, about 20 miles from Pyongyang.
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A North Korean Korean People's Army (KPA) defector driving along a road leading to the truce village of Panmunjom
This was the first time the North used this missile site.
The South’s response was calibrated to match the distance to the launch site to show