
Hong Kong police fired tear gas to break up a demonstration by thousands of masked anti-government protesters today as downtown Hong Kong turned into a battleground.

The protests happened in Victoria Park, a traditional venue for demonstrations and vigils, and the surrounding streets.

Police action was a fast response to a rally billed as an 'emergency call' for autonomy for the former British colony that was promised its freedom when it returned to Chinese rule in 1997.

The fast-moving crowds headed to the park through the Causeway Bay shopping district, some pulling up metal fencing to build street barricades, their actions masked by others holding umbrellas. Activists also threw at least one petrol bomb.

Many sang the British and U.S. national anthems, waved multi-national flags and a were calling for independence, a red line for Communist Party leaders in Beijing who have vowed to crush any such move.

Police using megaphones warned them to disperse, saying they would be prosecuted for holding an illegal assembly on the 22nd straight weekend of protest.

Police also raised a black flag, warning of tear gas, with activists running in all directions around the park.

Anti-riot Police Tactical Unit vans were already in waiting on the narrow side-streets around the Central business district to the west, the protester's destination for later in the afternoon.

Police pass a burning barricade to break up thousands of anti-government protesters who gathered in Hong Kong today

An anti-government protester is detained by policemen during a march billed as a global "emergency call" for autonomy, in Hong Kong, China

Medical volunteers help wash spray paint from a woman's eye as people attend a rally in Tsim Sha Tsui district in Hong Kong

Police in full gear pass burning debris as they walk the streets during a protest in Hong Kong today which saw violence escalate

Police in riot gear stand over people detained during a protest in Hong Kong on Saturday

Police used tear gas, pepper spray and water cannons to disperse protesters as huge numbers of them form a barrier as they walk down the street

A volunteer medic escorts a woman affected by tear gas during the protests which continued into the evening

Richard Chan, a candidate for district council elections, receives help after being pepper-sprayed by police during a pro-democracy rally in Hong Kong, China

A man with a fire extinguisher walks next to a vandalized shop during a pro-democracy rally in Hong Kong, China

Police officers fire tear gas at demonstrators during the protest. Police raised a black flag, warning of the gas, with activists running in all directions around the park

Police pass a burning barricade to break up anti-government protesters in Hong Kong, China

Pro-democracy protesters march on a street as they take part in a demonstration in the Causeway Bay district of Hong Kong

Pro-democracy protesters set a barricade on fire during a demonstration in the Causeway Bay district of Hong Kong today as violence escalated

Burning fire blocks a street during a pro-democracy rally in Hong Kong, China

Riot police fire tear gas to disperse protesters during a pro-democracy rally in Hong Kong, China

Richard Chan, a candidate for district council elections, lies on the floor after being pepper-sprayed by police during a pro-democracy rally in Hong Kong, China

A demonstrator stands near burning cardboard in the street during a protest in Hong Kong on Saturday

A protester receives first aid after tear gas was fired by police to break up thousands of anti-government protesters

Protesters make a fire with paper boxes as they attend a pro-democracy rally in Hong Kong, China

Riot police run through the streets as they attempt to control the unrest. Hong Kong is in its fifth month of mass protests

As protesters on Saturday began streaming into the park, police warned they were committing an offence

People protest during a march billed as a global 'emergency call' for autonomy next to the Causeway Bay shopping district in Hong Kong, China

Police fire tear gas to break up thousands of anti-government protesters during a march billed as a global 'emergency call' for autonomy

Riot policemen disperse protesters gathered for a march billed as a global 'emergency call' for autonomy, in Hong Kong, China

Police in riot gear gather near district council election campaign banners in Hong Kong

Hong Kong police have fired tear gas to break up a demonstration by thousands of masked anti-government protesters today as activists continue to call for democracy

Demonstrators wearing masks gather during an anti-government protest in Hong Kong on Saturday. Activists also threw at least one petrol bomb

Police officers in riot gear detain a man during an anti-government protest in Hong Kong. Protesters have taken to the streets for five months of sometimes violent unrest

An aerial view shows huge numbers of participants attending a pro-democracy rally in Victoria Park, Hong Kong, China on Saturday

Activists have attacked police with petrol bombs, started street fires and trashed government buildings and businesses seen as pro-Beijing

Protesters run away from the police during a pro-democracy rally in Hong Kong, China today

The police use a water cannon as one of their tactics to control the disruption which has spread across the area over the course of the day

Police using megaphones warned demonstrators to disperse, saying they would be prosecuted for holding an illegal assembly on the 22nd straight weekend of protest

Two men hold their faces in pain after police fired tear gas during a protest march billed as a global 'emergency call' for autonomy, in Hong Kong, China

Saturday's rally was not given official police permission, as is required, but that has not stopped people gathering in the past

Protesters walk through the rubble during the unrest today. Activists also threw at least one petrol bomb as the demonstrations escalated

Police officers in riot gear stand guard before an anti-government protest in Hong Kong, on Saturday. The rally was not given official police permission

Riot policemen detain a man in Causeway Bay district before a protest march in Hong Kong, China

Police action was a fast response to a rally billed as an 'emergency call' for autonomy for the former British colony that was promised its freedom when it returned to Chinese rule in 1997

This dramatic image shows demonstrators dispersing on a main road as police fire tear gas today in an effort to control the crowds

Defying a police ban, thousands of black-clad masked protesters are streaming into Hong Kong's central shopping district for another rally

An injured protester is assisted during a march billed as a global 'emergency call' for autonomy, in Hong Kong, China

Anti-riot Police Tactical Unit vans were already in waiting on the narrow side-streets around the Central business district to the west, the protester's destination for later in the afternoon

A protester stands in front of graffiti during the march today. Over the last months Police have responded with tear gas, pepper spray, water cannons, rubber bullets and occasional live rounds

Hong Kong is in its fifth month of mass protests, which were originally triggered by a now withdrawn extradition bill, and have since turned into a wider pro-democracy movement

Tear gas fired by police during a pro-democracy rally in Hong Kong, China. It has been used regularly as a tactic by law enforcement in recent months

Protesters run away from the police during a pro-democracy rally in Hong Kong, China. One protester Lulu, 55, said: 'It does not make sense for this assembly to be unauthorised'

A protester walks through the rubble during a march billed as a global 'emergency call' for autonomy, in Hong Kong, China today

Riot policemen disperse protesters gathered for a march. They have been dealing with the unrest for five months now in the city

The fast-moving crowds headed to the park through the Causeway Bay shopping district, some pulling up metal fencing to build street barricades, their actions masked by others holding umbrellas

Demonstrators wave British flags during an anti-government protest in Hong Kong today. Hong Kong is a semi-autonomous 'special administrative region' of China

Many sang British and U.S. national anthems, waved multi-national flags and a were calling for independence

Police officers in riot gear gather in front of a billboard during an anti-government protest in Hong Kong today

Participants attend a pro-democracy rally in Victoria Park, Hong Kong, China. This aerial shows the huge amount of people in attendance