South Korea test launches a cruise missile in this undated file footage.
Now, the country is extending the range of rockets like this one under a landmark agreement with the United States.
The pact, announced Sunday, will allow South Korea to develop missiles that can travel up to 800kms - more than twice the current ceiling.
Top security official Chun Young-woo said the deal was designed to deter an attack from the country's combative neighbour - North Korea.
South Korea has pushed for years to extend the range of its missiles - but long-time ally Washington resisted.
That stance changed after the North test-launched a long-range rocket in April - an attempt that ultimately ended in failure.
