OSAKA -- Universal Studios Japan, which is under investigation for improperly using and storing fireworks explosives, detonated an excessive amount of explosives this month in three of its attractions, officials from the prefecture and the company said Wednesday.

Osaka prefectural officials and police entered the Hollywood theme park Wednesday to inspect the three shows after USJ officials submitted a notice of change to the prefecture the same day. The shows were halted during the inspections, USJ officials said.

According to earlier investigations, the park has been using explosives that are different from those approved by the prefecture.