Riotous protesters who have degenerated Hong Kong with another weekend of turmoil involving fights and fires have drawn wide condemnation from society on Monday.

In a statement, the police severely condemned such violent acts which disregarded law and order. It said the force will continue to take resolute enforcement actions and bring all lawbreakers to justice.

As an illegal assembly turned ugly on Sunday afternoon, radical protesters attacked police officers with gasoline bombs and other weapons, set fires at multiple locations, and attacked others and reporters.

Mobsters also hurled bricks and gasoline bombs into the central government complex at Admiralty, forcing the adjacent Legislative Council building to issue a rare "red" alert that required everyone to leave the complex immediately.

At about 5:45 pm, around 20 radicals attacked two police officers and hurled several gasoline bombs at them at a short distance in Wan Chai. The officers had to withdraw pistols as a warning to disperse them.

During the mayhem, some thugs also attacked residents holding different opinions, beating one of them unconscious.

Having given repeated warnings in vain, the police used tear gas, rubber bullets, and specialized crowd management vehicles with water cannons to disperse radical protesters.

Some mobs also wreaked havoc at a number of MTR stations, with the Admiralty, Wan Chai and Causeway Bay stations suffering the most, despite the fact that the head of the railway operator said the city's railway system is on the brink of being unrepairable, after having been battered by radicalism and vandalism time and again.

Jacob Kam Chak-pui, chief executive officer of the MTR Corporation, said earlier on Sunday the company is finding it extremely difficult to locate parts to mend the damage amid sustained vandalism and attacks on the railway system. The cost may run up to HK$10 million ($1.28 million) for the more than 90 metro stations that were affected.

Train services at the three stations had to be suspended for public safety concerns.

In a statement issued on Sunday night, the MTR strongly condemned and expressed deep regret over the malicious acts.

The recurrence of violence and malicious vandalism at MTR stations not only severely affected passengers' journeys but also endangered the safety of passengers and MTR staff, the statement read.

Noting the cases have been reported to the police, the corporation said it will take suitable follow-up actions on the incidents and reserves the right to take legal action against the parties concerned.

The escalating violence also drew strong condemnation from prominent political parties.

Stressing that society should not tolerate any violent acts disrupting law and order, the New People's Party called on the authority to introduce anti-mask legislation as soon as possible to subside the unrest.

The Democratic Alliance for the Betterment and Progress of Hong Kong - the city's largest political party in the legislature – stressed that the protesters' malicious acts definitely cannot be tolerated.

In a statement issued late Sunday night, it reiterated the support for police to bring the rioters to justice. The party also urged all residents to immediately draw a clear line against violence and to not bear with such extremely violent acts.

To break the current political impasse, the party hopes the people of Hong Kong can join the government's efforts to solve the city's deep-rooted problems through dialogues.

The Hong Kong Federation of Trade Unions, the city's largest labor group, also deplored the rioters' outrageous acts, which have defied the law and spread hatred among society. The federation appealed to all sectors to unite together to bring order and peace back to Hong Kong soon.