The minister of defense caused a media squall after joking about invasions by space aliens and movie monsters. Responding to a question at a news conference, the minister, Shigeru Ishiba, told reporters that he was studying whether the nation’s pacifist Constitution would limit a military response to an attack by space aliens. “There are no grounds to deny that there are unidentified flying objects and some life forms that control them,” Mr. Ishiba said, smiling at first, but then delivering a straight-faced explanation. “If Godzilla attacked, that would probably be a natural disaster relief operation,” making military action legally permissible, he said. The comments came days after Japan’s chief cabinet secretary, Nobutaka Machimura, who is the government’s top spokesman, professed belief in U.F.O.’s.