Tokyo police have sent hundreds of officers to the Shibuya district, where a large number of people in costume gathered for Halloween.
Sidewalks around the famous scramble crossing near Shibuya Station were crowded with costumed revelers on Wednesday evening.
Officers with a public relations unit called "DJ Police" were calling on people to behave lawfully.
Many costumed people have flocked to the popular commercial district since the weekend. On Sunday, some Halloween revelers overturned a small truck.
Several people have been arrested on suspicion of assault or molestation.
Police will remain vigilant until early Thursday morning.
Shibuya Ward officials were distributing trash bags to around Shibuya Station.
This is response to large amounts of trash left behind on the roads. The officials said they have prepared 50,000 trash bags.
Some people who received the bags said they will bring their garbage back home.