Security chief Chris Tang told lawmakers that 517 people under the age of 18 had been prosecuted in connection with the 2019 protests by that date, adding that youths judged to hold "extreme ideological views" had been sent for "re-education."

"At present, all young persons in custody are required to receive Chinese-style marching training," Tang told the Legislative Council on Oct. 26.

"The Correctional Services Department emphasizes strict discipline training for young persons in custody, hoping to make them understand the importance of discipline and abiding by the law," he said.

"Juvenile inmates trained under the Rehabilitation Centres Ordinance are ... subjected to strict disciplinary training and hard physical training, to enable them to understand the cost of crime, and to reflect on their own misdeeds," he said.

Inmates are also required to undergo patriotic education and activities to "enhance their national identity, to instill the correct values ... and to help them rediscover meaning in life," Tang said.

They also take classes in "moral and civic education" and "national security law education," programs that have been imposed on children and university students across Hong Kong since the National Security Law sparked a citywide crackdown on public dissent and political opposition from July 2020.

"The Correctional Services Department will assign a dedicated case manager to assess these persons in custody to identify the special rehabilitation needs of each person in custody, and match each person in custody according to the three principles of the above-mentioned rehabilitation program," Tang said.