It's official: "Pokemon Go" monsters have invaded Japan, as evidenced by the legions of fans seen aimlessly wandering around the nation's streets far and wide — smartphones at the ready — in search of the gaming app's augmented-reality creatures.

And The Japan Times can confirm that Pokemon monsters have even been spotted inside the Prime Minister's Office in the nation's capital.

But there are also no-go zones where "Pokemon Go" characters are not supposed to be found: such as the nation's nuclear power plants.