Japan has deployed Patriot missile interceptors in key locations around Tokyo as a precaution to protect the 30 million people who live in Greater Tokyo against possible North Korean ballistic missile tests.
Two Patriot Advanced Capability-3 surface-to-air missile launchers were stationed at the defence ministry in Tokyo before dawn, a ministry spokesman said, while batteries would be deployed in two other locations in the greater Tokyo area.
Japan has taken similar measures before previous North Korean launches. It has never actually tried to shoot down a North Korean missile and was not expected to try to do so unless there was a clear threat to Japanese territory.
North Korea is believed to have moved ballistic missiles to its east coast, possibly in preparation for a test launch. That has further raised tensions on the Korean Peninsula amid threats by North Korea and large-scale war games involving US and South Korean troops.
''The government is making utmost efforts to protect our people's lives and ensure their safety,'' Japanese Prime Minister Shinzo Abe told presspersons today morning.
''As North Korea keeps making provocative comments, Japan, cooperating with relevant countries, will do what we have to do.
''For the moment, the most important thing is to implement sanctions under the UN Security Council resolutions,'' Abe said.
Tokyo's response thus far to the threats emanating from Pyongyang has been low key and today's moves are the most visible yet that it is rattled.
PAC-3 batteries will also be installed in the semi-tropical island chain of Okinawa, Onodera told a television programme broadcast yesterday.
He said Okinawa was ''the place that is most effective in responding to emergencies... so we should deploy the unit in Okinawa on a permanent basis''.
Japan's armed forces are authorised to shoot down any North Korean missile headed towards its territory, a defence ministry spokesman said on Monday.
In addition to the PAC-3s, Aegis destroyers equipped with sea-based interceptor missiles have been deployed in the Sea of Japan (East Sea), the defence official said.
Tokyo's moves came as North Korea said yesterday it was withdrawing all workers and suspending operations at a lucrative joint industrial zone with South Korea, with reports of heightened activity at the North's nuclear test site and at a missile battery.