HONG KONG: Riot police in Hong Kong launched volleys of tear gas and rubber bullets on Sunday during hours of running battles with pro-democracy protesters close to Beijing's office in the city, marking the second consecutive day officers have fired on demonstrators.

As the unauthorized protest occurred, the Hong Kong and Macao Affairs Office -- China's top policy unit for the two cities -- said in an unusual move that it would hold a press conference Monday afternoon in Beijing.

Hong Kong, a global financial hub, is reeling from weeks of anti-government protests that show no sign of abating.

Sunday's melees took place in a well-heeled residential district close to the Liaison Office, which represents Beijing in the semi-autonomous territory.

Police and protesters had been engaged in a standoff for hours after tens of thousands of demonstrators held a series of unsanctioned marches through the city.

A group of about 200 protesters had made their way towards the Liaison Office where they met a phalanx of riot police who used loudhailers calling for the crowds to end their "illegal assembly".

Eventually, tear gas and rubber bullets were fired at demonstrators who responded with volleys of bricks and stones as baton-wielding riot police pushed the crowds back in some of the most sustained and violent clashes seen during seven weeks of protest.

Specially-trained riot squad members, known as "Raptor" squads, made dozens of arrests, almost all of them young men and women. Several protesters were injured, as well as two journalists.

The clashes ended around 11:30 pm (1530 GMT) when protesters made a hasty and coordinated retreat into nearby subway stations.

Last week, they had pelted the Liaison Office with eggs and paint.

"Some radical protesters acted violently," threatening the safety of police and the public, the Hong Kong government said in a statement early Monday.

Sunday's violence came a day after police fired tear gas and rubber bullets at protesters holding a banned rally against suspected pro-government triad gangs in a town near the border with mainland China. The gangs had beaten up democracy demonstrators there the previous weekend.

- Unprecedented anger -

Despite facing unprecedented levels of public anger and frustration that has seen millions take to the streets, the city's pro-Beijing leadership are seemingly unable, or unwilling, to end the chaos.

Beijing's authority in the city of seven million is facing its most serious test since Britain handed it back to China in 1997 under a deal that allowed Hong Kongers to keep liberties including an independent judiciary and freedom of speech.

The demonstrations were triggered by a bill -- now suspended -- that would have allowed extraditions to mainland China, but have evolved into a call for wider democratic reforms and a halt to sliding freedoms.

Beijing has issued increasingly shrill condemnations in the last two weeks but has left the city's government to deal with the situation.

Pro-democracy lawmaker Claudia Mo said the city was now trapped in a "vicious cycle" where huge peaceful marches that have been ignored by the government end with violence between police and small groups of hardcore protesters.

"You see force being escalated on both sides. But then this is a huge imbalance because the police are in possession of deadly weapons. This sums up Hong Kong today," she told AFP.

- Battle for Yuen Long -

Public anger reached new levels a week ago when a pro-government mob of men wearing white shirts and armed with sticks attacked protesters in Yuen Long, in Hong Kong's rural New Territories where many of the surrounding villages are known for triad gang connections and their staunch support for the pro-Beijing establishment.

That brazen assault left at least 45 people taken to hospital, and police were heavily criticised for being too slow to respond.

In a rare move, police banned Saturday's rally saying they feared reprisal attacks against villagers from protesters.

They also banned a proposed march on Sunday. But on both days protesters simply ignored the orders.

On Saturday, small groups of more hardcore protesters, many in helmets and carrying shields, confronted police outside the villages and accused them of protecting triads.

Tensions quickly rose, leading to running battles between officers and protesters.

Police said they responded with "appropriate force" including rubber bullets, while at least four officers were injured.

Police made 13 arrests Saturday and hospital authorities said a total of 24 people were hurt, two seriously.