A 48-year-old knife-wielding man who allegedly slashed two people and bit off part of the ear of a politician has been arrested, along with two men who attacked him in return, Hong Kong police have said.

Senior police official John Tse said the man struck a couple with a knife outside a mall late on Sunday after an argument.

Mr Tse said the assailant, whose name was not given, was then beaten by an angry crowd, including two men aged 23 and 29.

All three were arrested following the incident.

Five people were injured, including two who were in critical condition, police said.

“We do not tolerate any form of violence regardless of one’s motive and political stance. We will certainly investigate fully and bring offenders to justice,” Mr Tse said.

Local media cited witnesses as saying that before going on a rampage, the man told his victims that Hong Kong belongs to China.

Television footage showed the man suddenly grabbing district councillor Andrew Chiu by the neck and biting his ear when Chiu tried to stop him from leaving after the attack.

A man was left unconscious on the ground in a pool of blood.

Hong Kong Protests
A double decker bus drives past burning debris during clashes between riot police and protesters in Hong Kong (Dita Alangkara/AP)

The incident occurred shortly after police stormed the mall and several other shopping complexes to thwart anti-government protests as tensions continue to mount after five months of unrest in the semi-autonomous Chinese territory.

Although Mr Chiu is a pro-democracy politician, it was not clear if that played any part in the attack.

“It shows that tempers are flaring up despite government claims to promote reconciliation,” said Willy Lam, an adjunct professor at the Centre for China Studies at Hong Kong’s Chinese University.

“It’s a sign that the situation is getting out of hand. People are losing patience and throwing rational judgment to the wind.”

Mr Tse said police arrested 325 people over the weekend.

“Rioters’ destructive acts serve no other purpose than to vent their anger and grievances, real and imagined. Continuing this rampage is a lose-lose situation for Hong Kong,” he said.

His comments were made through a Facebook Live broadcast after police called off their news conference when six journalists staged a protest and refused to leave.

Wearing helmets with words that read “Investigate police violence, stop police lies,” they were protesting against what they said was rising police violence against journalists covering the protests.

The demonstrations began in early June over a now-shelved plan to allow extraditions to mainland China, but have since swelled into a movement seeking other demands, including direct elections for Hong Kong’s leaders and an independent inquiry into police conduct.

Many protesters are angry that Beijing is slowly infringing on the freedoms guaranteed to Hong Kong when the former British colony returned to Chinese control in 1997.

There are no signs the unrest could stop any time soon as the government has refused to budge and Beijing has indicated it could tighten control over the territory.