A 27-year-old Swiss national who carried out an attack on a train Switzerland has died after sustaining injuries during the assault, Swiss police have said. He had been suffered from serious burns. The identity of the attacker has not been disclosed.

Policie from the St. Gallen canton described the suspect as a 27-year-old Swiss man from a neighboring state, AP reported.

Six people were injured after the man set fire to a train carriage and stabbed several passengers on board on 13 August. The attack occurred as the train was approaching Salez station, between the towns of Buchs and Sennwald.

A 34-year-old woman died from wounds sustained during the attack on Sunday 14 August.

The motive behind the attack is still unclear, but police ruled out the possibility of terrorism being behind the assault. "The question of motive remains," police from Switzerland's eastern Saint Gallen region said in a statement, saying: "To date there is no indication this was a terrorist or politically-motivated act."

"Terrorism is not our main theory," police spokesman Bruno Metzger told AFP, adding that "other motives" figured far higher on the list, but refused to give further information.

The other people who were injured in the attack are a six-year-old child who remains in a critical condition with life-threatening wounds, two men aged 17 and 50, and two women aged 17 and 43 . Some of the injured were said to be in a serious condition.

The attack occurred just weeks after an Afghan man attacked passengers on a train with an axe in the neighbouring German state of Bavaria. Four people were injured.

Earlier in July, a woman was killed and two people were injured in the German city of Reutlingen, near Stuttgart.

Swiss train knife attack
Policemen stand by a train at the station in Salez, eastern Switzerland, after a man set a fire and stabbed passengers on August 13 AFP/Getty