"...A ballistic missile would likely take around 10 minutes to travel 1,600 km (1,000 miles) from its launch pad in North Korea to Okinawa, it adds, citing a launch in February last year which took that length of time to fly over the Japanese island.
The warning comes as tensions ratcheted up between North Korea, its Asian neighbours and the US. The secretive communist state test-fired four ballistic missiles last month, three of which landed in Japan’s exclusive economic zone in the Sea of Japan, just off the coast of the country.
It has subsequently emerged that the country's civil defence website had 5.7 million visitors in the first 23 days of April — more than 14 times the usual monthly traffic..."