"They may be just testing the Japanese since they are preoccupied with the island issue" in the East China Sea, said James Hardy, a senior analyst for Asian Pacific region with Jane's Defense Weekly.

WSJ: Japan: Russian Fighter Jets Enter Its Airspace

"North Korea has short and medium range missiles that could complicate a situation on the Korean peninsula (and perhaps reach Japan), but we have not seen any evidence that it has long-range missiles that could strike the continental U.S., Guam or Hawaii, " wrote James Hardy, Asia-Pacific editor at IHS Jane's Defense Weekly, in a note to clients on Tuesday.

WSJ: North Korea Puts Artillery Forces on Combat Alert

"From what we know of its existing inventory, North Korea has short- and medium-range missiles that could complicate a situation on the Korean Peninsula (and perhaps reach Japan), but we have not seen any evidence that it has long-range missiles that could strike the continental U.S., Guam or Hawaii, " James Hardy, Asia Pacific editor of IHS Jane's Defence Weekly, wrote in a recent analysis.

NPR: SKorea: North Korea Moved Missile To East Coast