The Hong Kong government said on Monday it was outraged by the violence over the weekend and expressed its "severe" condemnation, after a police officer was injured by petrol bombs hurled by radicals on Sunday.

"We are outraged by the violent protesters' behavior which showed a total disregard of the law, posing a serious threat to the safety of police officers and other members of the public," said the spokesman.

Over the weekend, illegal protests took places in a "flash-mob-style" in various districts, causing severe damage to public property and disruptions of many public services. A police officer was hit by a petrol bomb thrown by a radical protester in Tsim Sha Tsui and suffered burns to his legs, according to the Hong Kong Police Force. Up till the end of Saturday, a total of nine police officers suffered eye injuries as hundreds of protesters intentionally aimed laser pointers at them. Among them, three were hurt on Saturday.

"There is no longer any defined period of time or fixed locations for these persistent and large-scale illegal and violent acts, depriving the right of ordinary people to carry on their daily lives," the spokesman said.

Appealing to the public to say no the violence and help the community to restore order as soon as possible, the government pledged that the police will enforce the law strictly and resolutely to bring illegal protesters to justice.

On Saturday, 16 people were arrested for unlawful assembly, possession of offensive weapons, assaulting a police officer and obstructing a police officer in the execution of duties.

City-wide condemnations also poured in after radicals hurled petrol bombs and injured a police officer.

Calling the act "atrocious and disregarding other people's life", president of the HKCPPCC (Provincial) Members Association Irons Sze called on the public to spare no efforts to support the police to bring the lawbreakers to justice.

Lawmaker Elizabeth Quat from the city's largest political party - the Democratic Alliance for the Betterment and Progress of Hong Kong, said the appalling act by the rioters showed that they were lawless. Quat, on her social media page, expressed hope for the injured police officer to get well soon.

Connie Wong Wai-ching, director general of the eighth Executive Committee of Kowloon Federation of Associations, one of the major local groups in the city, said she can't imagine that this kind of irrational act has happened in Hong Kong. The radicals have lost their minds and humanity, she added.