Kwok Ka-chuen, Chief Superintendent of Police, Public Relations Branch, made the remarks at a press conference on Monday.
On Sunday night, a private car suddenly drove through the police cordon line set in the vicinity of Austin Road and attempted twice to hit an officer. As warnings went in vain, an officer fired one shot at the car, which then quickly fled, Xinhua reported.
In the small hours of Monday, police arrested a 20-year-old woman for taking part in an unlawful assembly at the junction of Nathan Road and Jordan Road, and arranged an ambulance to send her to hospital as she sustained head injury.
A large number of rioters attacked the ambulance and took away the arrested woman. Two police officers were trapped inside the ambulance and attacked by rioters with stones, bricks and unknown liquids. With their lives under serious threat, an officer fired three warning shots.
Kwok said assisting offender is a serious offence and could lead to 10-year imprisonment.
Seven police officers were injured during the weekend, sending the total number of officers injured in the months-long violence to over 450, Kwok said.
Since June, the police have arrested 4,491 people aged between 11 to 83 over offences including unlawful assembly, rioting, possession of offensive weapon, arson, and assaulting police, among others.
( With inputs from IANS )