The protest started peacefully earlier in the day on Saturday (November 2) but quickly spiraled into chaos after police fired tear gas to disperse crowd at Victoria Park in Causeway Bay and nearby streets.
The protesters took off in all directions, many throwing bricks as they charged towards Central, building makeshift barricades on the way.
Buildings including China's official Xinhua news agency were also vandalised by protesters, in some of the worst violence to hit the city in weeks.
Saturday's rally was not given official police permission, as is required, but that has not stopped people gathering in the past.
Face masks were banned under a resuscitated colonial-era emergency law.