The night market has become popular over the years, with officials usually turning a blind eye. But police decided to issue tickets this year.
Reports of a crackdown against the hawkers who sell fish balls and other local food delicacies quickly spread on social media along with the hashtag #fishballrevolution.
More than 100 individuals are believed to have taken part and police told reporters today that 54 were arrested “on suspicion of assaulting and obstructing officers, resisting arrest and public disorder,” despite instructions to disperse, which included two midnight warning shots as heard in the video below.
"The government strongly condemns such violent acts," Hong Kong's Chief Executive Leung Chun-ying told reporters, adding: "The police will apprehend the mobs and bring them to justice."
The violence, which took place in a working-class neighborhood called Mong Kok, was the worst that the city had experienced since the wave of pro-democracy protests in 2014 known as the #umbrellarevolution.
The vendors' cause resonated with pro-democracy activists because of their concerns that local culture is disappearing as China tightens its hold on the semi-autonomous city.
Hong Kong’s “Localist” movement activists, who are calling for more autonomy from Beijing, were among those taking part in the protest. The group said on its official Facebook page that its candidate for local council, Edward Leung Tin-kei, had been arrested.
Police later said they did not expect another riot today when fireworks have been planned, but they will increase the numbers of officers on patrol as a precautionary measure.