Three young protesters involved in last year's social unrest — one who possessed five gasoline bombs, and two others who caused property damage of over HK$230,000 (US$29,700) — were sentenced to prison on Monday in two separate cases.

Law professor Willy Fu Kin-chi said the sentences are a wake-up call to those Hong Kong youngsters who intend to participate in illegal protests.

Lee Hoi-ching, a sophomore at the Open University of Hong Kong, received a one-year sentence for possessing offensive weapons in public.

The 23-year-old man had earlier pleaded guilty to carrying five gasoline bombs during an illegal assembly in Mong Kok on Oct 31, when protesters blocked traffic and started fires on the streets.

Lee was arrested later during a dispersal operation against about 100 protesters at the scene. After he was apprehended, police seized five gasoline bombs inside a backpack he had left in an alley.

Principal Magistrate Peter Law Tak-chuen said the case is very serious, considering the destructive power of gasoline bombs. Because of Lee's guilty plea, Law decided on the one-year sentence after shortening the term of imprisonment by six months.

In another sentencing on Monday, 21-year-old twin brothers were ordered to serve seven weeks in prison for damaging railway facilities in September.

Leung Ho-long and Leung Tsz-long were arrested after damaging turnstiles, ticket vending machines and screens worth HK$230,000 at a light rail station in Tin Shui Wai with four others at about 2 am on Sept 7.

Asking for leniency, the defense attorney said the two young men felt remorseful, ashamed and unfilial, adding that the brothers' mother blamed her own lax parenting for her sons' behavior.

Cheung reduced the prison term from 15 weeks to seven weeks for the pair because both brothers had pleaded guilty to criminal damage two weeks ago, and restitution had been paid to the railway operator.

Magistrate Kathie Cheung Kit-yee said the crime was premeditated, as the twins had prepared tools and extra clothes for the plot.

She cautioned that violence or other illegal acts can never be a means to voice demands, adding that she hopes the twins will get a fresh start.

A total of 8,337 people have been arrested so far in connection with the violent protests since June. Of those suspects, over 1,600 have been prosecuted, with the top three charges being rioting, possession of offensive weapon, and unlawful assembly.

In an interview with China Daily, Fu, the law professor, said that as courts gradually resume operations as the pandemic eases locally, an increasing number of protesters will pay the price for their misconduct during last year's unrest.

Fu, also vice-chairman of the Hong Kong Legal Exchange Foundation, believes the jail sentence could serve as a deterrent to the city's young people, some of whom plan to plunge the city into another round of chaos.

Anti-government protests have returned to the city's streets and shopping malls since late April as the coronavirus pandemic came under control. On Mother's Day, May 10, groups of protesters staged illegal assemblies across the city and had violently clashed with police officers. About 230 radical protesters were arrested that day.