Two Hong Kong pro-democracy activists have pleaded guilty to charges related to an illegal assembly during mass anti-government protests in August 2019.
Seven others, including media tycoon Jimmy Lai, pleaded not guilty.
The protests, fuelled by a perception Beijing was curbing the wide-ranging freedoms promised to the former British colony upon its return to Chinese rule in 1997, plunged the semi-autonomous city into crisis.
The August rally was estimated to have drawn more than a million people, despite heavy rain, and provided a respite from clashes between protesters and police seen often in the months before and after.
Former pro-democracy politician and activist Au Nok-hin pleaded guilty to organising and knowingly taking part in an unauthorised assembly, while fellow activist Leung Yiu-chung pleaded guilty to participating in an illegal assembly.
They will hear the verdict on March 22.
The other seven, including prominent Beijing critic Lai, Democratic Party founder Martin Lee, and veteran activists Lee Cheuk-yan and Leung Kwok-hung, known as Long Hair, pleaded not guilty to the charges.
The latter two shouted "Object to political prosecution!" when making the plea.
Beijing responded to the 2019 protests by imposing a sweeping national security law in June last year, punishing anything China deems as secession, subversion, terrorism or collusion with foreign forces with up to life in prison.
Since the introduction of the law, the government has disqualified opposition politicians and jailed activists, while authorities have banned slogans, songs and pro-democracy political activity in schools.
Lai has been in custody since December and is scheduled for another court appearance on Thursday for his appeal against an earlier decision to deny him bail in relation to charges of colluding with foreign forces.