The attack took place on Saturday afternoon
Six people have been hurt after a man set a train carriage on fire in Switzerland and stabbed several passengers
The alleged attacker, who is a Swiss citizen, was also injured when the train was set alight as it travelled in the far east of the country along the border with Liechtenstein.
Swiss police say the possibility of terrorism seems "very, very far-fetched" - however, they are not excluding the possibility it was a crime of passion.
A six-year-old child is among those who were injured as the train travelled between Buchs and Sennwald at 2.20pm local time (1.20pm GMT). The victims also include two men aged 17 and 50, as well as three women aged 17, 34 and 43.
A police spokesman has said the attacker and one of his female victims are in a very serious condition in hospital, and that their lives are in danger.
It has been reported that the attacker targeted one woman in particular by dousing her in flammable liquid.
In a statement, St Gallen Police added: "According to current information a 27-year-old Swiss man poured out a flammable liquid. He was also armed with at least one knife. The liquid caught fire."
Several dozen passengers were on the train when the incident began, police added, and a "massive contingent" of police, firefighters, rescue helicopters and paramedics attended the scene.
Nearby Salez station was closed as a criminal investigation began.