The violence was less sustained than Saturday when police and protesters fought hours of cat and mouse battles after thousands took the streets for an unsanctioned march.
But the day ended with a knife attack taking place outside a shopping mall in Tai Koo Shing, a middle-class neighbourhood on the main island where protesters had gathered for much of the afternoon.
Eye-witnesses told local media that a Mandarin-speaking man attacked people shortly after shouting pro-Beijing slogans.
Live footage showed Andrew Chiu, a local pro-democracy councillor, having his ear bitten off after trying to subdue the attacker, while a second man was seen unconscious in a growing pool of blood as bystanders desperately tried to stem wounds to his back.
The alleged assailant, wearing a grey t-shirt, was then beaten bloody by the crowd until police and other emergency workers arrived.
Hospital authorities said five people were wounded, four men and one woman. Two victims were in a critical condition, two were serious and one was stable. Police revised down their wounded toll from six to five people and said three people were arrested, without detailing whether the alleged knife attacker was among those counted as injured or arrested.