A museum commemorating the deadly 1989 Tiananmen Square crackdown has been raided by Hong Kong police.
Four members of the group that ran the museum, the Hong Kong Alliance, were detained on Wednesday - including prominent pro-democracy activist and barrister Chow Hang Tung, reports BBC.
The arrests were made under the national security law, which has a maximum sentence of life imprisonment.
Police have accused Ms Chow of inciting subversion, her lawyers said.
The group, known for organising the city's famed annual vigil for Tiananmen Square victims, denies accusations of being a foreign agent.