Hong Kong police detained prominent democracy activist Chow Hang-tung, with authorities determined to prevent any protests on the anniversary of Beijing's deadly Tiananmen crackdown.
Thousands of officers were on standby after the government banned an annual candlelight vigil that has served for decades as a day of pro-democracy people power in the city.
The first arrest came early Friday morning when Chow Hang-tung, one of the few remaining prominent democracy activists not already in jail was detained by four officers outside her office.
Chow, 37, is one of the vice-chairs of the Hong Kong Alliance which organises the annual vigil.
A police source said Ms. Chow had been arrested under section 17A of the Public Order Ordinance, which covers publicising unlawful assemblies.
This year's vigil has been banned by Hong Kong police, who cited the coronavirus pandemic even though the city has not recorded a case of unexplained local transmission in more than a month.
Last year's vigil was also banned on the grounds of the coronavirus. Tens of thousands defied the ban and rallied anyway in the park.
Police later arrested some two dozen democracy figures who attended that rally, some of whom have been given prison sentences, including other members of the Hong Kong Alliance.