Blood was seen running down the man’s face as he was being treated by a first-aider. It’s not clear what hit him but a friend said he saw him fall to the ground after he heard rounds of tear gas being fired.
Officers were seen firing tear gas from a window at Tin Sum Police Station down onto people in the street.
Police were trying to clear a group who had gathered outside and had been hurling abuse at officers.
The crowd went there after police detained two people nearby. This sparked anger and objects were thrown at officers as they left. Officers then fired two sponge rounds to disperse the crowd.
In Tsuen Wan, several explosions were heard after a small group of protesters hurled petrol bombs at the regional police headquarters for the New Territories South.
A group of police officers, who were behind the gate, fired tear gas to disperse them.
They are part of a group of people who responded to online calls to vent their anger at the police over Tuesday’s shooting of an 18-year-old student in the district.
They marched through the town and vandalised some shops.
At a mahjong parlour, they broke through the shutter and smashed what they could.
They also spray-painted protest slogans on the shutters of an arcade game centre, a China Mobile outlet and two mainland bank branches.
The entrance of one of them, Bank of China, was set on fire and its ATM machines were vandalised.
Earlier, nearly a thousand protesters staged a rally at a nearby playground before dividing into different groups and setting off to block roads.
In Wong Tai Sin, dozens of people put up barricades on Lung Cheung Road. An elderly man was injured after receiving blows to the head following a confrontation with anti-government protesters.
Witnesses said he had earlier been waving a chopper at some of them. Later footage showed a chopper lying on the ground.
And a large group of people in Causeway Bay also occupied the section of Hennessy Road outside Sogo department store. This protest ended largely peacefully
The government has condemned the action of the protesters and said police would take resolute action to restore public order.