How have other governments dealt with violence among mass protests?

Mass protests across the world often put local police in a sensitive position. In Hong Kong, anti-fugitive bill protests have been going on for nearly three months amid increasing violence. The Hong Kong authorities have faced criticism over their handling of the protests with the police being accused of "abusing its power and overuse of violence." However, since June 9, when the protests broke out, more than 200 police officers have been wounded. Some of the police's families are even under threats from radical protesters.

In the context of public law, citizens have a constitutionally protected right to engage in peaceful protest, but petition of protest should be turned down if the protest disrupts other people, advocates imminent violence and brings chaos to public order.

So, how have other places dealt with violence among mass protests?