Watch: Hong Kong on lockdown-Student, 18, is shot in chest by cop

Hong Kong police have urged the public to stay indoors after an 18-year-old protester was shot in the chest by an anti-riot officer during a clash.

Another policeman has been filmed shouting at onlookers, demanding them throw Molotov cocktails at anti-government 'rioter' protesters as the city is rocked by unprecedented level of violence amid China's National Day celebrations. 

The injured demonstrator was hit in the chest by a police officer in the city's Tsuen Wan district this afternoon and was taken to Princess Margaret Hospital.

Debris from the bullet was lodged in his chest only an inch from his heart and he is in critical condition, according to reports. He is said to be a secondary school pupil.