The force warned residents authorities would take decisive action against any illegal acts, adding it was carefully watching whether any residents were intent on committing seditious acts or encouraging others to harm national security or public safety.

Local media reported that two activists staging a hunger strike were taken away by police. According to local media, one was Kwan Chun-pong, a former volunteer with the Hong Kong Alliance in Support of Patriotic Democratic Movements of China, which organised past vigils, and the other was Lau Ka-yee, a member of the support group Tiananmen Mothers.

The two were planning to begin their 24-hour hunger strike at 6.04pm but were detained, the reports said.

Officers were also seen taking two artists away on East Point Road outside the Sogo department store not far from the park. Artist Sanmu Chan was heard chanting “Do not forget June 4! Don’t be afraid of them, Hongkongers!” as two officers held his arms while more surrounded him.

Artist Chan Mei-tung was also stopped and taken away. Officers at the scene did not respond to media inquiries about whether they had been arrested.

A petition signed by 360 pastors and other Christian figures in the city will be published in the Christian Times on Sunday, and among the signatories is Reverend Chu Yiu-ming, one of the co-founders of the Occupy Central civil disobedience campaign in 2014.

“Lord! We must admit that distortions in politics, imbalances in society and the diaspora phenomenon will bring us fear … May the Lord give us greater confidence and courage, so that we will be fearless and not be scared by changes,” the prayer read.

The three-day carnival, co-organised by 26 pro-Beijing groups to mark the 26th anniversary of Hong Kong’s return to Chinese rule on July 1, opened in the morning with 200 booths offering traditional snacks and folk art performances, including music and dancing.

At the opening ceremony, Chief Secretary Eric Chan Kwok-ki said the event would highlight different parts of the nation and help stimulate consumption.

A steady stream of visitors filled the carnival ground in the morning despite the sweltering heat. The mercury rose above 32 degrees Celsius, according to the Hong Kong Observatory, which issued a special hot weather alert at 1.30pm.

“Today’s vibe is excellent with a lot of people. It’s only that we are all sweating profusely,” said veteran entertainer Natalis Chan Pak-cheung, who was offering a free tasting of canned abalones and mooncakes sold under his brand.

Hong Kong security chief warns troublemakers ahead of June 4 anniversary

He urged Hongkongers to get used to the absence of June 4 vigils and move on.

“The mainland has not held vigils, and it’s been the same for them. Under ‘one country, two systems’, we’re integrating into the nation and putting the economy first,” he said, referring to the governing principle adopted upon the handover.

Out of the six soccer pitches at Victoria Park, the carnival is occupying four from Saturday to Monday, while two others were fenced off for maintenance.

The lawn north of the pitches was also off-limits to regular park users as part of it was under maintenance, while the rest was occupied by game booths and inflatable bouncers set up by the carnival organisers.

Thousands of police officers to patrol Hong Kong on Tiananmen Square anniversary

For decades, Hongkongers gathered in those open spaces every June 4 to remember those killed in the crackdown in Beijing in vigils organised by the Hong Kong Alliance in Support of Patriotic Democratic Movements of China.

The alliance’s attempts to hold the vigils in 2020 and 2021 were blocked by authorities citing public health risks during the Covid-19 pandemic. There were no attempts to hold an event in 2022 or this year after the organisation disbanded in 2021.

A carnival visitor in his thirties, who identified himself only by the surname Chan, said his memory of attending a vigil a few years ago felt remote.

“To be frank, even if there was no such [carnival], the application for a June 4 [vigil] would not have been accepted,” said the man, who works in manufacturing.

In addition to the numerous police officers on patrol, visitors, who had to pay HK$5 (63 US cents) for admission, were also subject to a bag check by security guards.

“My family and I were surprised to see so many cops,” said Ng Hoi-chun, a 29-year-old interior fit-out worker, who was leaving the fair after finding the offerings “so-so”.

He said he had taken part in the vigils with his family from a young age, and he last participated in 2018. This year he planned to take an evening walk with friends to mark the date. “I believe some spontaneous activities will take place. They won’t all be gone,” he said.

Hong Kong cinema cancels private screening on ‘sensitive’ June 4, group says

Wilson Leung, who was strolling in the park with his family, said he had also attended vigils in the past, but would now look to his friends before deciding whether to mark the occasion.

“We’ve been talking less about politics because of the national security law. I wouldn’t go out on purpose if there were not so many friends going together,” he said, referring to the law imposed by Beijing three years ago.

Security chief Chris Tang Ping-keung last month warned “resolute action” would be taken against anyone taking advantage of the “special occasion” to threaten national security, although officials have avoided specifying what action types of behaviour would trigger a response.