The Government today strongly condemned rioters for their extreme and violent acts on October 1.
In a statement, it said there had been online orchestration of violent acts in various districts across the city yesterday and it incited people to go on a rampage and attack police officers.
The violent attacks caused multiple injuries and police officers were required to use their revolvers in a few cases, the Government said.
The Commissioner of Police said that the life of the police officer involved in the open fire incident in Tsuen Wan was under serious threat, it noted.
It added that under police guidelines, appropriate force has to be deployed if police warnings are not heeded.
A man suffered a gunshot wound and was sent to the hospital. His current condition is stable, according to the Hospital Authority.
The Government said many people took part in the unauthorised meetings and processions yesterday.
Violent protesters set fires inside Mass Transit Railway stations, threw petrol bombs, vandalised shops and public property and blocked thoroughfares, causing serious obstruction to firefighting and ambulance work.
The mob also damaged Cheung Sha Wan and Tsuen Wan Government Offices, the statement said.
Additionally, they challenged the national sovereignty by burning national flags in Central and Causeway Bay.
The Government said the riots on October 1 were planned and organised, leading Hong Kong to a chaotic state.
It added this reflects that the nature of the issue has already changed and that society does not want to see students breaking the law.
It appealed to parents and teachers to advise young children and students not to participate in unauthorised public meetings and processions, and to stay away from violence.