Protesters walk down the road with traffic cones to build a barricade in Causeway Bay, Hong Kong. Image Credit: Reuters

Hong Kong: A man was set ablaze after he engaged in a heated argument with a group of pro-democracy demonstrators during the ongoing anti-government protest in Hong Kong on Monday.

Graphic video of the incident posted on social media shows an unarmed man wearing a green t-shirt shouting expletives at protesters before saying "you're all not Chinese." He is then doused with a flammable liquid and set alight by a person present on the spot.

A Hong Kong police source told CNN they are investigating the incident which took place at the Ma On Shan subway station in the New Territories. The man is in hospital in a critical condition, Hong Kong's Hospital Authority said.

The incident occurred hours after two protesters sustained injuries after being shot at by a traffic police officer in Hong Kong on Monday morning.

Footage from the scene of the incident, which took place in Sai Wan Ho, show a traffic police officer firing a live round into the abdomen of another protester who was approaching him. Two more rounds were subsequently fired at another protester.

Washington Post quoted a police spokesperson as confirming that live rounds were fired and that two protesters were injured outside the Sai Wan Ho MTR station and taken to Eastern Hospital for treatment.

The anti-government protests in the city escalated yesterday over the death of Chow Tsz-lok, a computer sciences student at Hong Kong University of Science and Technology (HKUST). Chow had suffered a severe head injury in a parking garage close to the scene of protests.