Japan's military should be ready at any time to shoot down any North Korean missiles that threaten to strike Japan, newly appointed defence minister ordered on Monday. A state of alert for at least three months was also put in force.
Tomomi Inada issued the order without mentioning any indication that Pyongyang is preparing to launch such a missile, public broadcaster NHK said
NHK said Inada is expected to renew the readiness order every three months so that Tokyo can seamlessly maintain a state of alert.
A Japanese defence ministry spokesman declined to confirm the report.
Tomomi Inada was appointed on Wednesday, the same day North Korea, a major security headache for Japan, fired a ballistic missile that landed just 250 kilometres (155 miles) off its coast -- hitting Japanese-controlled waters for the first time.
After Wednesday's launch Japanese media quoted officials as saying they were surprised and voicing concern that North Korea was getting better at concealing its preparations to fire missiles.