It added, “Violation of airspace by foreign unmanned reconnaissance balloons and other means is totally unacceptable.”
Beijing hit back on Wednesday, saying Japan lacked evidence.
Foreign Ministry spokesman Wang Wenbin told reporters, “Japan is making baseless accusations and defaming China without conclusive evidence. We strongly oppose it.”
Japanese media said government officials were relaxing rules on shooting down aerial objects that violate its airspace.
For the time being, weapons can only be used in case of a clear and present danger, Kyodo news agency reported.