Putting an end to violence in Hong Kong is the city's most important task, China's Foreign Ministry said yesterday, as state media condemned an escalation in violence and urged tougher police action.

Foreign Ministry spokesman Geng Shuang said this objective has the "broadest consensus" and "loudest voice" in Hong Kong.

"China's central government firmly supports the Hong Kong SAR government in administering the law, and supports the Hong Kong police in strictly enforcing the law, protecting social order and the safety of Hong Kong citizens," said Mr Geng at a regular press briefing.

His comments come after a marked escalation in violence beginning on Monday morning when a protester was shot by police after he tried to grab the officer's service revolver. That same day, a 57-year-old man was set on fire as he argued with protesters who were trying to block roads.

Mr Geng also hit back at criticism from the United States and Britain about the police's use of force, and said no country would allow the snatching of an officer's firearm, or allow him to be attacked while he was carrying out his duties.

"These actions will be strongly countered by the police. You can ask the US and UK officials, if these incidents happened in the US or UK, how would their police deal with them?" he said.

The unrest in Hong Kong has continued for more than five months now, but the developments on Monday marked one of the most violent days yet.

It drew unanimous condemnation and some of the harshest words yet from state media.

Mr Hu Xijin, editor of the nationalistic Global Times, compared protesters to the Islamic State in Iraq and Syria (ISIS) terror group. The newspaper said in an editorial: "When necessary, the People's Armed Police Force and the People's Liberation Army Hong Kong Garrison will back (the police) up in accordance with the Basic Law."

State broadcaster CCTV said the chaos in Hong Kong was a "battle between life and death" and the only response will be "the most severe enforcement".

The Chinese Communist Party's People's Daily also hinted that stopping the violence was a requirement if the city's district council elections are to go ahead.

"Support the police to decisively put down the riots - only then can there be a return to peace and the holding of fair elections. Only this can help Hong Kong find a new start," it said.