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 approached wearing a face mask, the officer fired at him, hitting him in the torso.
As the grapple continued, the officer fired another two rounds – although police said only one person was injured in total.
There have been a number of other flashpoints during the day, with police firing rubber bullets and tear gas in others parts of Hong Kong.
At one point, tear gas was fired in the central business district – a rare occurrence during working hours on a weekday.
The shooting 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 a man was shot.
After the shooting, footage showed the 21-year old protester lying with his eyes wide open and with blood around him.
He was in critical condition and underwent surgery, a Hospital Authority spokesman told the BBC.
The police said officers also drew firearms from their holsters in two other places.
But they 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.