Edited sentence: Anarchists frequently accuse police and state authorities of provoking violence.For example, on N30, after the police began firing CS and OC at protesters, some protesters began breaking windows at the sponsors of the WTO meeting.In general, movement leaders tend to encourage peaceful protest as the more productive way of getting attention and respect for their goals, although occasionally protests do turn violent.Many prominent Non-governmental Organizations (NGOs) dispute this view, saying that physical damage or property destruction is inherently violent.Many, such as anarchists who participate in the Black Bloc tactic argue that breaking windows is not necessarily a violent action unless humans beings are harmed in the process.Some have also criticized the movement for engaging in violent or destructive protest.There is a debate within the movement over what is defined as violence