Police arrested 13 people between Wednesday and Thursday in Tokyo's Shibuya Ward for alleged groping, assault and theft as a massive crowd of Halloween revelers swamped the district.
The 13 arrested were men ranging from their teens to their 40s, the police said.
Several hundred police officers were dispatched to the area to control the crowd, including some special officers dubbed "DJ police," who aim to marshal crowds in a light-hearted manner.