Hong Kong activist Chow Hang Tung has been released on bail a day after she was detained over a vigil to commemorate the 1989 Tiananmen Square crackdown on pro-democracy activists in Beijing.

Police arrested Chow, vice-chairperson of the Hong Kong Alliance in Support of Patriotic Democratic Movements of China, alleging she promoted an unauthorised assembly early on Friday morning.

“There’s no logic in that. It’s a completely absurd charge, a complete abuse of power. I reject all the allegations,” she told reporters outside the police station on Saturday.

The ban on the vigil and at least six arrests came amid growing concern in the pro-democracy movement and internationally about the suppression of the semi-autonomous city’s traditional freedoms, notably a national security law imposed by Beijing last year.

It’s inspiring to see people in Hong Kong commemorate the Tiananmen Square massacre despite efforts by Beijing and Hong Kong authorities to silence their voices. We call for the immediate release of those arrested for peacefully memorializing June 4.

— Secretary Antony Blinken (@SecBlinken) June 4, 2021

“I want to tell all who participated in this suppression of the Tiananmen remembrance event this year … don’t hide behind the technical provision of the public order ordinance anymore,” Chow said.

“Open your eyes and see what you are actually doing, what you are actually doing is to cover up the crime of the killers in 1989.”

No right to assemble

On Friday the authorities sealed off Victoria Park, site of the world’s largest Tiananmen vigils for more than three decades, to enforce a ban on the annual assembly for a second year due to coronavirus restrictions.

Some churches opened their doors for memorial masses for the victims of Tiananmen, with people filling up the venues amid fears of being arrested on the streets.

In an unprecedented diplomatic gesture amid the police ban on the vigil, candles flickered in the windows of the United States consulate and European Union office in the city.

Although Chow could not light a candle while detained, she said she fasted during her detention.

Chow was released with cash bail of HK$10,000 ($A1600) and is due to report to the police station on July 5.

Lee Cheuk-yan, the alliance’s chairperson, is in jail for an illegal assembly in 2019. Chow herself is facing a charge of inciting and participating in an illegal assembly on June 4 last year.

-AAP