Police said before midnight that a 53-year-old woman was arrested for obstructing officers after she refused to show her identity card at Victoria Park. Officers also detained 11 men and 12 women, aged 20 to 74, for suspected breaches of the peace, the force said.

Among them was Chan Po-ying, the leader of the League of Social Democrats opposition political party and who was carrying an LED candle and yellow paper flowers.

Leo Tang Kin-wah, former vice-chairman of the disbanded Confederation of Trade Unions, was escorted into a police vehicle after being searched by officers and taken to the station in Wan Chai. He was wearing a black T-shirt with a print of the front page of the Chinese-language newspaper Wen Wei Po from June 5, 1989.

Police also led away the former chairwoman of the Hong Kong Journalists Association, Mak Yin-ting, and activist Alexandra Wong Fung-yiu, known as “Wong Po Po” or “Grandma Wong”, as she stood on Great George Street holding a bouquet of flowers. Some passers-by chastised police for taking action against an elderly woman.

Officers detained a man carrying a book about the play May 35 by Candace Chong Mui-ngam, which tells the story of a woman seeking to hold a vigil for her son killed in Tiananmen Square during the student-led protests in 1989.

A man surnamed Pang, 35, said he was searched after taking pictures of police vehicles out of curiosity. An attendee of past vigils, Pang said he would commemorate the event in his own way.

“I have told my children about the incident,” he said. “No one can change history.”

4 Hong Kong protesters arrested near Victoria Park ahead of June 4 anniversary

Political activist Frances Hui said Chow Hang-tung, who belonged to the now-disbanded vigil organiser, the Hong Kong Alliance in Support of Patriotic Democratic Movements of China, had been placed in solitary confinement for staging a 34-hour hunger strike.

Chow is serving 4½ months in prison for refusing to assist a police investigation into the alliance’s alleged breaches of the national security law. She is also facing a separate trial at the High Court involving the group.

A 54-year-old woman was arrested for carrying two straps with seditious wordings and laying out items with seditious intent, according to police. Another woman, 50, and a man, 51, were arrested for holding papers featuring seditious phrases and refusing to cooperate after repeated warnings, the force said.

Ronny Tong Ka-wah, a member of the city leader’s key decision-making body, the Executive Council, advised residents to avoid taking part in any organised commemoration.

But Tong said he believed Hong Kong remained a diverse and free society under the “one country, two systems” governing principle and he respected everyone’s right to mark such events as they saw fit.

Beijing expected Hong Kong to be a “stable and peaceful society”, he said, adding Chinese people should unite as the country came under threat from foreign political forces.

Greater clarity needed on how to legally mark the June 4 anniversary

Bishop Stephen Chow Sau-yan of the Catholic diocese of Hong Kong posted a prayer on social media and described June 4 as “a particularly thought-provoking day” for many residents.

“Pray for those whose hearts have hardened that they will gradually be softened and relieved from deep-seated fears and anxieties,” he wrote.

The carnival, staged by 26 pro-Beijing groups, features 200 booths offering traditional snacks and folk art performances, as well as music and dancing.

A spokesman for the organisers earlier denied the three-day event that ends on Monday was aimed at blocking other uses of the space and said it was intended to mark the 26th anniversary of Hong Kong’s return to Chinese rule on July 1.

While the American consulate declined to comment further on its June 4 arrangements, US Secretary of State Antony Blinken said his country “will continue advocating for people’s human rights and fundamental freedoms in China and around the world”.

Additional reporting by Harvey Kong, Oscar Liu and Danny Mok