ZURICH: Six people were injured in an attack aboard a Swiss train on Saturday by a man armed with a knife and flammable fluid, St Gallen cantonal police said. Three adults, two teenagers and a child aged six were hurt, according to a police statement. Five were stabbed or burned. A sixth suffered smoke inhalation as he came to the aid of the others. The assailant, a Swiss citizen, was also injured. '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,' the statement said. Authorities did not yet know the motive for the attacks but a crime of passion was one possibility, Bruno Metzger of the St Gallen cantonal police said in an interview with welt.de. 'A terrorism background still seems very, very far-fetched,' Metzger said. The assailant was in police custody, he said, but none of those injured - including the assailant - was responsive, so they could not be questioned. The police said a criminal inquiry was under way. Both a woman and the attacker were in critical condition, according to Swiss broadcaster SRF, citing the St Gallen police. The cantonal police did not respond to a request for further information by email and could not be reached by phone. The attack occurred at 2:20 pm (08:20 am EDT) as the train neared the Salez station on a trip between Buchs and Sennwald in St Gallen, a canton in the northeast of the Alpine republic, the police statement said. It was the first attack of its kind in Switzerland in recent memory. In December 2015, a 33-year-old Swiss man broke into his neighbors' house in Rupperswil and killed four people before setting the house on fire, an incident that shocked the country.