At least 17 people have been injured after fire engulfed a train carriage in Hong Kong's underground system.

Police have arrested a man for suspected arson. They said there was no evidence that terrorism was a motive.

Media reports said a man had tried to throw a petrol bomb inside the carriage during evening rush hour.

Social media users have been sharing a video showing a man lying on the platform engulfed in flames, as other passengers try to douse the fire.

The train was travelling from Admiralty to Tsim Sha Tsui station. Two of the injured are said to be in a critical condition.

The South China Morning Post reported that a man had shouted "burn you to death" before lighting a petrol bomb but then caught on fire himself.

Police District Commander Kwok Pak-chung said a 60-year-old man had been arrested.

"According to investigation up until now, we believe this incident was related to the personal issues of one person, an independent incident. No information at this point shows that it was an act of terror or an attack targeting public transportation," he said.

Underground employees later extinguished the blaze.

Hong Kong's RTHK broadcaster showed people in a smoke-filled train carriage, describing the situation as "chaotic".

Hong Kong Chief Executive Leung Chun-ying called for a full investigation.

The Mass Transit Railway (MTR), the company that runs the underground, later announced that Tsim Sha Tsui station was closed and there was service disruption on the Tsuen Wan line.

Hong Kong's transportation network is known for its safety and efficiency, and such incidents are rare.