Japan's Defense Minister Takeshi Iwaya says the two short-range ballistic missiles launched by North Korea on Saturday were a new type of weapon.
Iwaya told reporters on Tuesday that his ministry arrived at the judgment after comparing the launches to other missiles and projectiles North Korea has fired in the past.
On Sunday, the Korean Central News Agency reported that the country's leader Kim Jong Un oversaw a test of a newly developed "super-large multiple rocket launcher." Saturday was the seventh day of test firings by Pyongyang since July 25.
Iwaya said North Korea may be seeking to heighten the secrecy and immediacy of its missile launches to make it hard to detect their signs. He added that the North may also be trying to improve accuracy and its ability to mount surprise attacks.
Iwaya noted that Pyongyang is developing missiles that travel at a lower altitude than normal and on an irregular path and said this may be aimed at breaching defense systems.
He said Japan will reinforce its comprehensive anti-air missile defense system so that it will be able to respond to any aerial threats.