Japan is planning to deploy a new ground-based missile defence system as its third layer of protection in response to the North Korean ballistic missile threat, local media said yesterday.
This additional layer, known as the Aegis Ashore system, will supplement its current defences that Tokyo has acknowledged could be woefully inadequate in the case of a North Korean missile attack.
Japanese Defence Minister Itsunori Onodera, who is currently in Washington, was likely to sound out his United States counterpart, Mr James Mattis, on the plan.
The duo, alongside Japanese Foreign Minister Taro Kono and US Secretary of State Rex Tillerson, were slated to meet for high-level "two- plus-two" talks that began at 9.45am US time yesterday (9.45pm in Singapore).
The Aegis Ashore system, to be developed by Lockheed Martin, the world's biggest weapons manufacturer, is the land-based version of the Standard Missile-3 (SM-3) advanced radar units mounted on Aegis warships that patrol Japan round the clock.
The SM-3 can intercept ballistic missiles outside the earth's atmosphere by up to an altitude of 500km.
Japan owns four destroyers equipped with the SM-3, also known as the Aegis advanced radar system, and two of them are being refitted. Public broadcaster NHK reported yesterday that Japan is mulling over the adoption of a fifth SM-3-equipped destroyer.
Separately, Japan also has 34 units of the Patriot Advanced Capability-3 (PAC-3) missile interceptor system, which has limited range: It can destroy targets at altitudes of only between 10km and 20km.
Last week, PAC-3 units were deployed in the western prefectures of Shimane, Hiroshima, Kochi and Ehime, following North Korea's detailed threats to fire missiles over the Japanese mainland towards the US territory of Guam.
Any missile fired by North Korea towards Guam will still be on the ascent as it flies over Japan, defence experts have said, which means the SM-3 might stand a better shot of intercepting the rocket.
But the PAC-3 will still be able to shoot down stray missiles that could fall in Japan due to failure mid-flight, as well as rocket debris.
The meeting between the Japanese and American defence and foreign ministers comes as North Korea has demonstrated progress in its ballistic missile and nuclear programme that it said is necessary to deter a US-led invasion.
Last week, it threatened to lob a volley of four missiles into waters around Guam after US President Donald Trump said he will unleash "fire and fury like the world has never seen" on the isolated North, which last month had successfully launched two inter-continental ballistic missiles. Both sides have since toned down their rhetoric.
On Wednesday, Mr Kono and Mr Onodera met US National Security Adviser H.R. McMaster. The trio agreed that their countries must "avoid a contingency situation" in responding to the threat.