Riot police have stormed several shopping centres in Hong Kong in a move to thwart more pro-democracy protests.

But violence did break out when a knife-wielding man slashed several people and bit off part of the ear of a local pro-democracy politician.

The move came as the city’s leader heads to Beijing for talks on deepening economic integration between the semi-autonomous Chinese territory and mainland China.

There were calls online urging protesters to gather in seven locations to sustain a push for political reform following a chaotic day of protests and clashes with police on Saturday, with the anti-government movement showing no signs of letting up after nearly five months.

Hong Kong Protests
A man walks past posters with Chinese words reading ‘Peaceful protesters and frontliners stand together’ at a shopping mall in Hong Kong (Dita Alangkara/AP)

Most of the rallies did not pan out Sunday as scores of riot police took up position, searching and arresting people, dispersing crowds and blocking access to a park next to the office of embattled chief executive Carrie Lam.

Nevertheless, small pockets of hardcore demonstrators managed to cause some trouble.

As some protesters chanted slogans at the New Town Plaza shopping mall in Sha Tin, police said they moved in after some “masked rioters” with fire extinguishers vandalised turnstiles and smashed windows at the subway station linked to the mall.

In two malls in the New Territories in the north, protesters vandalised shops, threw paint and attacked an outlet of Japanese fast food chain Yoshinoya, which has been frequently targeted after its owner voiced support for the Hong Kong police.

Police rushed into one of the malls after objects were thrown at them. At another, protesters used umbrellas and cable ties to lock the mall entrance to prevent police from entering.

Later on Sunday, police stormed the Cityplaza shopping complex on Hong Kong Island after some protesters sprayed graffiti at a restaurant. A human chain of dozens of people was broken up and angry shoppers heckled the police.

Hong Kong Protests
Police fired tear gas during clashes with protesters on Saturday (Dita Alangkara/AP)

On Sunday night outside Cityplaza, a man slashed several people with a knife and bit off part of the ear of a district councillor who was trying to stop him from leaving. Local media said the man told his victims that Hong Kong belongs to China.

Television footage showed the man biting the councillor’s ear and being badly beaten up by a crowd after the attack, before police arrived. At least five people were injured, reports said.

The protests 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.

Ms Lam has refused to budge on the demands, and instead has focused on measures that she said contributed to protesters’ anger, such as creating jobs and easing housing woes in one of the world’s most expensive cities.

Last month, she invoked emergency powers to ban face masks at rallies, provoking further anger.

Her office said on Sunday that Ms Lam, currently in Shanghai, will head to Beijing on Tuesday.

She is due to hold talks with Chinese Vice Premier Han Zheng on Wednesday and join a meeting on the development of the Greater Bay Area that aims to link Hong Kong, Macao and nine other cities in southern China.

The ambitious project will help make it easier for Hong Kong residents to work and reside in mainland Chinese cities, and bolster the flow of people and goods, Ms Lam’s office said in a statement.

But the plan has also sparked concerns over China’s growing influence over the territory. Many protesters fear Beijing is slowly infringing on the freedoms guaranteed to Hong Kong when the former British colony returned to Chinese control in 1997.

Hong Kong Protests
China’s Xinhua News Agency office in Hong Kong was damaged by protesters on Saturday (Kin Cheung/AP)

On Saturday, protesters for the first time attacked the Hong Kong office of China’s state-owned Xinhua News Agency in a show of anger against Beijing, a day after China warned of tightening its grip on the city to quell the unrest.

The attack on Xinhua came after chaos broke out in the city centre, with police firing tear gas and protesters throwing petrol bombs.

Xinhua said in a statement that it strongly condemned the “barbaric acts of mobs” that had vandalised and set fire to the lobby of its Asia-Pacific office building.

The Hong Kong Journalists Association also deplored “any act of sabotage against the media” and called for an end to violence against the press.

Protesters have frequently targeted Chinese banks and businesses.

In July, demonstrators threw eggs at China’s liaison office in Hong Kong and defaced the Chinese national emblem in a move condemned by Beijing as a direct challenge to its authority.

On Friday, the Communist Party in Beijing vowed to “establish and strengthen a legal system and enforcement mechanism” to prevent foreign powers from sowing acts of “separatism, subversion, infiltration and sabotage” in Hong Kong.

Hong Kong Protests
Demonstrators build a barricade in the street (Vincent Yu/AP)

Hong Kong, which has a separate legal system from mainland China, has tried to enact anti-subversion legislation before but failed amid public opposition.

Beijing may be indicating it is preparing to take matters into its own hands by having the National People’s Congress – a ceremonial legislature – issue a legal interpretation to enact such legislation.