A policeman has shot a protester during another day of violent demonstrations in Hong Kong.
Footage posted on Facebook showed the officer drawing his gun before grappling with a man at a roadblock.
When another man wearing a face mask approached the officer he fired at him, hitting the protester in the torso.
As the grapple continued, the officer fired another two rounds. It was not clear from the footage whether the bullets hit anyone.
There were a number of other clashes on Monday, with police firing tear gas and rubber bullets in others parts of Hong Kong.
The shootings occurred as protesters tried to block a junction at Sai Wan Ho on the north-east of the island. Police confirmed that one officer “discharged his service revolver” and that “one male was shot”.
Footage showed the protester lying with his eyes wide open and with blood around him. He was undergoing surgery and was in critical condition, a Hospital Authority spokesman told the BBC.
Authorities said that at two other places officers also drew their firearms from their holsters. But police denied what they called “totally false and malicious” reports that officers were ordered to “recklessly use their firearms” in Monday’s operations.
It was the third time a police officer shot someone with live rounds since the Hong Kong protests began in June. The first incident was during protests on 1 October when China was celebrating 70 years of communist rule. The second case was a teenage boy shot in the leg on 4 October.
While most protests have taken place at weekends, protesters called for a general strike – that is, all workers not to work – on Monday.
In addition to the shooting, other clashes included:
Police described the activists as “radical protesters,” conducting “extensive illegal acts” and urged them to stop any actions that threaten safety and obstruct the police.
Several universities have cancelled their classes for the day.
The latest violence comes after a student died in hospital last Friday after falling from a ledge in a car park, reportedly trying to flee from police tear gas.
Hong Kong is part of China but as a former British colony it has some autonomy and people have more rights .
The protests started in June against plans to allow extradition to the mainland – which many feared would undermine the city’s freedoms.
The bill was withdrawn in September but demonstrations continued and now call for full democracy and an inquiry into police behaviour.
Clashes between police and activists have become increasingly violent and in October the city banned all face masks .