Japan has deployed Patriot missile defence systems in central Tokyo ahead of a planned DPRK rocket launch expected to cross Japanese territory next week.

Last week Japan began deploying Patriot Advanced Capability-3 (PAC-3) ground-based interceptors to islands in the country's southern Okinawa prefecture.

The deployment of two PAC-3 launchers to central Tokyo, and others to bases around the capital, completes the country's deployment of the land-based interceptor system.

Japan is also deploying three Aegis radar-equipped destroyers carrying Standard Missile-3 interceptors to the sea between Japan and South Korea.

The DPRK is expected to launch the rocket some time between April 12th and 16th in the direction of Japan's southerly Okinawa prefecture and Taiwan.

Pyongyang says it is merely sending a weather satellite into space, but South Korea and the United States claim it is a disguised ballistic missile test.