Police had earlier on Friday arrested a 59-year-old security guard on suspicion of spreading threats on social media proclaiming to kill officers during an unlawful assembly on Saturday to mark the anniversary of the 1989 crackdown.

Chief Inspector Tai Tze-bun, of the cybersecurity and technology crime bureau, said the man was arrested in Tai Po in connection with inciting others to inflict grievous bodily harm with intent. The man’s laptop was also seized.

“Our investigation is still going on. We won’t rule out making more arrests,” he said.

Hong Kong police warn against ‘unlawful assemblies’ on June 4

Tai said cybersecurity police targeted the man after they found that some people had distributed and published messages online to incite violence and hatred against certain parties.

“We recently noticed that someone had used the online platform to encourage people to hold unlawful assemblies on June 4. This person declared that he would carry out illegal acts during the assembly, including hurting or killing police,” he said.

“After investigations, we targeted the man as the suspect.”

Tai added the man might also be held for contempt of court as he was suspected of breaching an interim High Court injunction imposed in 2019 that forbade him to disseminate messages on social media or other channels to incite violence.

Police respected people’s freedom of speech and right to assemble, but “are against and condemn those who use the online channels to incite hatred and advocate violence”, Tai added.

Following the arrest, the department announced plans to lock down large parts of Victoria Park from 11pm on Friday for more than 24 hours. People who had booked the venue facilities on June 4 would be informed of the closure, the spokesman said.

Hong Kong June 4 activities will be subject to laws: Carrie Lam

On Thursday, police warned residents not to participate in any “unlawful assemblies” after authorities banned the candlelight vigil marking the anniversary of the June 4 crackdown for a third straight year.

The force said there were online calls encouraging people to participate in unlawful assemblies around the park on Saturday.

Hong Kong was the only city on Chinese soil to organise large-scale activities to mourn those killed in Beijing’s Tiananmen Square, but for the past two years, authorities banned the event citing public health concerns related to the Covid-19 pandemic.

The Hong Kong Alliance in Support of Patriotic Democratic Movements of China, the group behind the annual candlelight vigil, disbanded last September in light of the national security law.

An estimated 20,000 people still turned up at Victoria Park in 2020, including 26 opposition leaders who were later arrested and charged.

As most of the park was closed last year, residents held much smaller commemoration events scattered across the city amid a heavy police presence.

At least 100 police officers arrived to patrol Victoria Park at 11pm on Friday, while security in other parts of Causeway Bay was strengthened earlier in the evening.

At around 9pm, a woman was taken away in a police van after carrying out a performance on East Point Road in Causeway Bay and attracting dozens of onlookers.

The woman peeled potatoes, and raised five fingers in a performance that ended when she took out a lighter and attempted to “light” one of the vegetables.

“She was rolling a potato over her body and peeling it, and the peelings were all over the ground and then police led her away,” said Kwan, a security guard who was nearby.

Separately, a man also staged a performance on nearby Lockhart Road. He lay on the road in the evening holding a bundle of long leaves in his mouth, before unfurling a scroll on the ground and lighting a candle at the end of it.

Additional reporting by Justin Chan