Japan has started deploying its Patriot missile defence system after North Korea threatened to fire ballistic missiles over the country towards the US Pacific territory of Guam. <br/><br/>Public broadcaster NHK said the defence ministry started deploying the Patriot Advanced Capability-3 system in Shimane, Hiroshima and Kochi in western Japan, which Pyongyang warned could be along its missiles' flight path. <br/><br/>NHK said the defence ministry is also to deploy the anti-missile system in neighbouring Ehime. Japan has in the past vowed to shoot down North Korean missiles or rockets that threaten to hit its territory.