A total of 15 juveniles, aged between 12 and 15, have been arrested for their suspected roles in the protests against the now-abandoned extradition bill, Hong Kong Police Force said on Tuesday.

According to the police, the offences include unlawful assembly, assaulting police officer, obstructing police officer, loitering, possession of offensive weapons, and possession of instrument fit for unlawful purposes.

The youngest among the 15 protesters was arrested for unlawful assembly. He had just finished his elementary schooling and was about to start junior high school in the upcoming academic year.

Li Chi-lam, principal of Lingnan Hang Yee Memorial Secondary School, confirmed on social network that a student of the school was arrested on August 25.

Under the Juvenile Offenders Ordinance, no child aged between 10 and 13 can be sentenced to imprisonment; and no person aged between 14 and 15 can be sentenced to imprisonment if that person can be suitably dealt with in any other way.

Ho Hon-kuen, chairman of Education Convergence, said he was saddened to see underage taking part in those illegal assemblies. He added the incident rang an alarm bell in the education sector, which should draw an in-depth reflection on liberal studies.

Liberal Studies is a required subject in the Diploma of Secondary Education curriculum. The subject, intended to cultivate critical thinking and positive values, has come under fire for not serving that purpose.