The officer, who is now in a stable condition, had been on duty near the Sogo department store. His assailant, a 50-year-old man, died after stabbing himself in the chest.
In a statement, the force said some people had been posting messages online and encouraging others to pay tribute and mourn the attacker in a bid to “glorify, romanticise, make heroic and even rationalise the blatant violence”.
A police spokesman said this was “no different from supporting terrorism”.
“It will incite further hatred, divide the society and eventually breach social order and endanger public safety, threatening everyone in Hong Kong,” he warned.
“Members of the public should remain rational, discern fact from fallacy and not to tolerate or glorify violence. We should not let misinformation mislead the next generation into going astray or even worse to become terrorists.”
The police said even though an initial probe suggests the attack was a ‘lone wolf-style act of domestic terrorism’, its national security department will take over the case and investigate whether there was any accomplice involved, whether the attacker was incited by others, and whether there was any person in control behind the scene.
The force appealed to anyone who has information to contact them via the national security reporting hotline.