Tang said a 28-year-old officer from the police tactical unit had to undergo surgery at Queen Mary hospital after being stabbed in the back outside the Sogo department store in Causeway Bay at around 10pm.
Video purportedly of the incident showed a man stabbing the officer from the back without warning, before the victim staggered away.
Police say the suspect – a 50-year-old man whom they did not identify – subsequently stabbed himself and was later pronounced dead after he was taken to Ruttonjee Hospital.
The officer’s lung was punctured and he suffered 10-centimetre-deep wound, Tang said.
“Initial investigations indicate that this is a lone wolf-style act of domestic terrorism,” Tang told reporters after visiting the officer in the early hours of Thursday morning.
“It’s not just the assailant who has to be held responsible for this incident, but also the many people who customarily advocate violence, incite hatred against the country, and beautify these attacks – these acts of violence. In fact, these are the primary factors that have led to this unfortunate incident.”
“Besides the assailant, the people pushing him from behind… these peoples’ hands are also covered in blood,” he added.
The new security chief, though, did not specify whether or how the authorities would take action, or who they would target.
He said there’s no evidence yet to show that anyone else was involved in the attack, but a search of the suspect’s apartment showed that he had been ‘radicalised’.
The attack happened at the end of a day that saw 19 people arrested across the SAR for various alleged offences including possessing weapons and insulting the national flag, as thousands of officers were deployed to stamp out any sign of protest, on the 24th anniversary of the handover.