Scores of people have been injured in Hong Kong during a chaotic weekend of anti-government protests that left one man in a critical condition.

Twelve police officers were also injured during the weekend clashes, with more than 300 people ranging from 14 to 54 years of age arrested between Friday and Sunday, police say.

Chinese state media on Monday called for a tougher line against the protesters, who vandalised the local offices of state-run Xinhua news agency and other buildings, saying the violence damaged the city’s rule of law.

Reporters are seen wearing helmets with anti-police slogans.

More demonstrations are planned this week to keep up pressure for demands that include an independent inquiry into police behaviour and universal suffrage.

Pro-democracy lawmaker Charles Mok said people were “heavy-hearted”.

“They don’t know what is going to happen tonight or maybe the next weekend. And there is a lot of worry,” he said.

More than 100 demonstrators, some wearing now-banned face masks, returned on Monday evening to a shopping centre where a man had knifed several people on Sunday (local time) and bitten off a part of a politician’s ear before being beaten by protesters.

Those who gathered on Monday shouted at security guards and riot police who also briefly entered the complex in the eastern suburb of Taikoo Shing.

Police said they arrested three men involved in Sunday’s incident, including the suspected 48-year old assailant.

Riot police had stormed several shopping malls to disperse protests near families shopping on Sunday.

It followed the worst violence in weeks on Saturday, when police fired tear gas, rubber bullets and a water cannons at crowds of black-clad demonstrators across the Chinese-ruled financial hub.

The city’s Hospital Authority told Reuters one person was in a critical condition, with two others serious, among a total of 30 injuries from Sunday alone.

Local media reported a life-threatening injury was sustained by a male student who fell from a height, but details of the incident remained unclear.

The head of the boy’s university called on authorities to investigate the matter in a heated dialogue on campus with students on Monday evening (local time).

While Hong Kong and its many businesses function normally during the week, many protests have sprung up spontaneously at weekends over the past five months.

Pro-democracy protesters are campaigning against what they see as Chinese meddling with the freedoms promised when the former British colony returned to Chinese rule in 1997.

China denies doing so, and has blamed Western countries for stirring up trouble.

-AAP