Lam Chi-wai, the chairman of the Junior Police Officers’ Association, made the comments in a letter to his fellow members.
In footage of the event captured outside Tuen Mun Town Hall on Saturday, protesters were seen trying to pull objects from the officer’s waist-belt while he was detaining a suspect.
The footage showed one protester snatching the officer’s baton and beating him with it while other protesters joined in with sticks and umbrellas.
In the melee, another person looked like they were trying to grab the officer’s gun, but failed and was driven away policemen who arrived to stop the attack.
Lam slammed the “rioters” over the attack, warning that their actions are getting bolder and they have crossed a line.
He said pistols are the “second life” of officers while they’re on duty, and they will use every method to protect their revolvers.
“If someone tries to steal an officer’s gun, that means they’re taking the life of the officer. Rioters, are you psychologically prepared to make the step to threaten the lives of police officers and others?” Lam asked in the letter.
“If you take that step, we will have no choice but to make the only and necessary decision. Please think twice,” Lam added, without elaborating.
He also urged public figures to break their silence and condemn the violence of protesters, adding that he only sees the top government officials, the force, and a few legislators seriously speaking out against the protests so far.