Footage shows protesters inside a shopping mall in Hong Kong singing a song of defiance against mainland China on May 21.
The group were bellowing "Glory to Hong Kong," a march song popularised last year during the unrest against the authoritarian regime.
The video was taken inside the Landmark mall in the Central district.
Violence has subsided during the pandemic, but a new protests have flared up as China proposes a controversial new security law.
Local media claimed that the new rules would ban secession, foreign interference, terrorism and activities which could be interpreted to be aimed at toppling the under-pressure communist government.
The laws would also ban any external international involvement in the former British trading outpost.