Tokyo police say a vehicle has been damaged by people wearing Halloween costumes in the Shibuya district.
The streets around Shibuya station were crowded with young people and foreigners until the early hours of Sunday morning.
Police say Halloween revelers gathered around a small truck and overturned it at around 1 AM.
Fights also broke out. Some people were arrested for sexual offences.
Police officers are being deployed in the area again on Sunday evening.