Hong Kong Police on Monday denounced the violent protests that erupted in multiple locations during the past weekend after a lull of several weeks, accusing the rioters of acting like "gangsters" by attacking passers-by and vandalizing shopping malls.

At a news conference, Chief Superintendent of the Police Public Relations Branch Kwok Ka-chuen compared the rioters' actions to the sparks of a dying mountain fire. But the resurgence of violence they ignited was enough to "burn the whole city", Kwok warned.

On Sunday afternoon, a passer-by was besieged by black-clad rioters who smashed her cellphone after the woman took photos of them in the New Town Plaza at Sha Tin. Outside the Sha Tin metro station, a rioter hurled a smoke bomb at a crowd of passengers waiting at the bus terminal.

In the past week, eight police officers were injured, while 99 suspects from 12 to 54 years old were arrested for offenses that included unlawful assembly, attacking police officers, and assault, according to Kong Wing-cheung, senior superintendent (media liaison and communication) of the Police Public Relations Branch.

Kwok said that of the 31 arrested on Sunday, 17 were students, adding that the statistic was "worrisome". He stressed that people who exploit immature juveniles to commit crimes to achieve their own selfish goals are "despicable".

Since October, police have received over 1,200 reports of crimes involving various degrees of damage at 897 locations across Hong Kong, Kwok said.

He reiterated the police's determination to safeguard law and order and bringing offenders to justice, and called on the public to say "no" to violence while providing useful information to assist police investigations.