The Japanese government's top spokesperson says North Korea is apparently trying to boost its ability to conduct surprise attacks.
Chief Cabinet Secretary Matsuno Hirokazu made the comment on Friday. He was responding to reports that the North has launched a "tactical nuclear attack submarine."
Matsuno said it is likely that Pyongyang is trying to enhance its ability to carry out surprise attacks, which are hard to intercept, grasp and detect. He said that having the ability to launch ballistic missiles from various platforms, such as submarines and vehicles with launch pads, could enable the North to conduct surprise attacks.
He also said Tokyo recognizes that North Korea's military capabilities pose a serious and imminent threat to Japan's security.
Matsuno went on to say that Japan will do its best to surveil North Korea. He added that Japan will gather intelligence about the North and conduct analyses.