Japan yesterday issued the order to shoot down a North Korean rocket if it threatens the nation's territory, the top government official said.
Tokyo has readied surface-to-air missiles in and around Tokyo, and Okinawa, and is putting its armed forces on standby ahead of Pyongyang's planned missile launch. It is also deploying Aegis warships in neighbouring waters.
Defence Minister Satoshi Morimoto has told forces to destroy the projectile or any parts that look set to fall on Japanese territory, Chief Cabinet Secretary Osamu Fujimura said.
Once Pyongyang launches the rocket, Japan's government "will swiftly deliver information" to local authorities, as well as to broadcasters and directly through Twitter and other social media," Fujimura said.
"We would like people to carry on as normal because the missile won't fall towards Japan if all goes as expected."
Pyongyang announced last week a window from Monday to December 22 for its second attempt at a long-range rocket launch this year after a botched attempt in April.
Pyongyang insists it is a peaceful satellite launch, but the international community sees it as a test of ballistic missile technology, which is banned under UN Security Council resolutions.
New satellite images indicate snow may have slowed preparations for the launch, but that Pyongyang could still be ready for lift-off starting on Monday.
South Korean media reports this week quoted unnamed officials in Seoul as saying North Korea had mounted all three stages of the Unha rocket on the launch pad by Wednesday. But snow may have prevented Pyongyang from finishing its work by then, according to GeoEye satellite images from Tuesday that were released yesterday.
US Pacific forces commander Admiral Samuel Locklear said in Washington on Thursday North Korea wanted to "demonstrate to the world that they have the capacity to be able to build missiles and have the missile technology to be able to use it in ways of their choosing down the road".
Additional reporting by Associated Press