A student journalist suffered a serious head injury on Monday night while covering protests outside the Sham Shui Po police station in Hong Kong.

Ryan Lai Ka-wai, a Year 3 university student from Chu Hai College and a freelance cameraman with Visible Record – a non-profit organization advocating for the art and culture of documentary film – was struck by a canister of tear gas fired by police, public broadcaster RTHK reported.

He was knocked out and had heavy bleeding from a wound to his left forehead. Other journalists nearby said riot police charged forward into them, raising the black tear gas warning flag, even though the journalists shouted that one of them had been hurt and was receiving treatment.

Officers continued to shove their shields towards the journalists to block them from taking videos of what was happening.

A reporter named Chow Chun-fung came forward and tried to stop the police. During the chaotic confrontation, the reporter grabbed an officer’s collar for defense as he was about to throw a punch. Chow was then forced to the ground by an officer, who took him into the station where he was detained for 15 minutes.

Chow, from the Ta Kung Pao publication, and was released without charge.

According to a report by the pro-Beijing newspaper, it was a misunderstanding between their reporter and police which was resolved during his stay in the police station.

Meanwhile, both Visible Record and the Chu Hai College Student Union condemned the police on their social media platform for using “excessive force” by firing tear gas at people.

Lai was reportedly taken to the emergency department at Caritas Medical Centre and was in a stable condition.