Police said they had arrested more than 310 protesters between Tuesday and Thursday, 165 of them on Christmas Eve, including 105 near the force’s headquarters in Wan Chai, on suspicion of taking part in an illegal assembly.

A 19-year-old protester was injured after leaping over a railing from the first floor to the ground level of the Yoho shopping centre in Yuen Long to evade arrest that day.

Police published a Facebook post on Thursday morning, warning that “guns have entered the community”.

“If members of the public come across any pistol- or rifle-like objects or suspicious articles, please leave immediately and make a report to the police when the situation allows,” the post read.

The government also hit back at allegations that protesters’ rights were being violated with the use of excessive force.

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“Violence has indeed escalated in recent weeks, including serious acts that endanger public safety and public order by blocking roadways, paralysing traffic, setting barricades, committing arson, vandalising shops and railway facilities, hurling bricks, throwing petrol bombs, flagrantly assaulting bystanders and violently attacking police officers,” a spokesman said.

“Increasingly lethal weapons including petrol bombs, catapults with steel ball bearings, explosive devices, bombs, bows and arrows have been used by radical protesters who have shown up well equipped with helmets, shields, goggles, respirators, masks, full body armour and protective gear. Such preparations are indicative of their intention to stage violent protests and directly confront and attack police officers, which mitigate the effectiveness and efficiency of lower level of force available to the police through standard anti-riot weapons.”

The city’s embattled leader, Chief Executive Carrie Lam Cheng Yuet-ngor, weighed in with a Facebook post on Wednesday to accuse protesters of ruining Christmas celebrations.

The defiance continued on Boxing Day, with dozens of masked activists marching through Tai Po Mega Mall at about 1.30pm, prompting many stores to close.

Police restrained at least two men outside the mall and more inside, while one officer was seen spraying blue-dyed pepper spray at a woman at close range.

After police took control of the atrium and searched demonstrators as well as reporters at the scene, the Hong Kong Journalists Association condemned a masked officer for demanding and displaying the identity card of a Stand News reporter on camera during the online portal’s live broadcast.

The reporter was singled out by police after he chased a baton-wielding man, demanding to know if he was a plain-clothes officer.

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The reporter said he would complain to the privacy watchdog, while the association lamented that in exposing his private information, police had effectively doxxed him.

The association accused police of harassing and physically attacking reporters doing their job. Police in turn have accused people in press vests of obstruction during anti-riot operations and siding with protesters.

Masked protesters also targeted other shopping centres in the city’s tourist districts on Thursday, including Langham Place and Moko in Mong Kok, Sogo in Causeway Bay and V city in Tuen Mun, where riot police pepper-sprayed activists marching through the mall and detained several of them.

At the Moko atrium, protesters chanted slogans for hours, including a new one: “January 1, meet at Victoria Park”, referring to a mass rally on New Year’s Day planned by the Civil Human Rights Front, which has organised the biggest protests over the past seven months.

They also heckled customers at restaurants and coffee shops owned by mainland Chinese-linked businesses, including Urban Bakery and Pacific Coffee, cheering as people were forced to leave.

Armed riot police entered the mall and protesters threw potted plants and black paint or ink at them.

Police stopped and searched groups of people as bystanders heckled them.

A teenager at the protest who gave her name as Wendy had a message for the city’s leader: “If she thinks we are ruining Christmas festivities, has she thought about who caused this situation in the first place?”

A jewellery shop supervisor at Harbour City, where protesters gathered to sing songs and chant slogans, said sales had dropped by up to 50 per cent compared with last Christmas. She was worried about more losses over the coming Lunar New Year holiday, and blamed both protesters and police.

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“It takes two to tango … I believe every stakeholder in society should shoulder some responsibility for the current situation,” she said.

Yeung Wai-sing, chairman of the Association for Hong Kong Catering Services Management, said hotel buffet services during the festive season had been hit particularly hard.

“Protests have largely dampened people’s mood to celebrate by going out for luxury dining in busy districts,” he said.

Yeung added that several Chinese restaurants in protest-hit areas planned to shut down before the Lunar New Year as their tenancies expired.

Jason Wong Chun-tat, chairman of the Hong Kong Travel Industry Council, said the number of mainland Chinese tour groups visiting Hong Kong over the Christmas holidays had plunged to about 10 groups per day on average, only 10 per cent of the number recorded over the same period last year.