Authorities in the Canadian city of Montreal said they briefly detained more than 240 people and arrested a dozen for more serious offences during a protest against police brutality late Friday.
Two officers were hurt in the annual event that usually results in violence.
As a helicopter hovered overhead, hundreds of police -- on foot, horseback, in cars and on bikes -- were dispatched to oversee the march, which was deemed illegal because organizers had not provided route details to authorities.
Those arrested were taken in for alleged assaults on police or for being in possession of incendiary objects. Two police officers were hurt.