Japan has begun moving Patriot guided missiles to the country's north-east to possibly shoot down a North Korean rocket.

Spy satellite images have confirmed the hardline communist state has placed the rocket on the launch pad.

Pyongyang insists the rocket is carrying a communications satellite into space and has said it could fire it as early as this weekend.

The United States and Japan says it is a cover for a ballistic missile test.

Spy satellites have photographed the nose cone of the rocket on the launch pad in North Korea, but it is unclear if it is carrying a satellite or a warhead.

Tokyo is threatening to shoot the North Korean rocket down if it threatens Japanese territory.

Meanwhile the US Defence Secretary Robert Gates says the US has no plans to shoot down the missile if the test goes ahead.