The police reportedly had to use tear gas twice.
In a separate development, law enforcement officers pepper-sprayed protesters at the Cityplaza shopping mall after the latter vandalised two restaurants with graffiti.
The South China Morning Post, in turn, reported that a knife-wielding man had attacked protesters near a shopping mall in Tai Koo after a harsh political exchange. The knife attacker injured four people before the crowd violently beat him. As a result, a district councillor also had part of his ear bitten off by the attacker.
A man who tried to protect the attacker was also injured, so was a young woman. The knife-wielding man was later arrested by police.
Five people were rushed to hospital as a result, with two of them in critical condition.
This weekend saw one of the worst violence in weeks, with protesters setting fire to metro stations and trashing the regional office of China's Xinhua news agency. The unrest, initially triggered by the now-withdrawn extradition bill, has been on since June.
Law enforcement officers maintain that they use force proportionately and only in response to violent acts or unlawful behaviour by the protesters. Beijing views the situation in Hong Kong as a result of foreign interference in China's domestic affairs and expresses full support for the actions of the local authorities.