Tokyo, Aug 12 (IANS): Japan said on Saturday it has installed anti-missile systems in several parts of the country following North Korea's threat to launch four ballistic missiles towards the American island of Guam.

The surface-to-air Patriot Advanced Capability 3 (PAC 3) has been deployed in the prefectures of Shimane, Hiroshima, Kochi and Ehime, the expected flight path of the North Korean projectiles, reports Efe news.

Pyongyang on Thursday threatened to launch a ballistic missile attack against Guam in the western Pacific, where some 160,000 people live and where strategic bombers sent by the Pentagon are stationed.

The plan unveiled by Pyongyang detailed the launch of four medium-long range Hwasong-12 rockets that will cross the sky above Shimane, Hiroshima and Kochi prefectures at a distance of 3,356.7 kms for 1,065 seconds (nearly 18 minutes) before hitting the waters 30 to 40 km away from Guam.

Japan's anti-missile defence operation system deploys the navy's Aegis to bring down airborne missiles while the PAC-3 system is used to counter the projectiles evading these interceptors.