A man stabbed three people at a train station in Winterthur, a city of around 123,000 residents in northeastern Switzerland near Zurich, in an attack that authorities have formally classified as an act of terrorism. The assault took place at approximately 8:30am local time on Thursday, during the tail end of the morning rush hour. The suspect, a 31-year-old Swiss-Turkish dual national who lives in Winterthur, was arrested within five minutes of emergency services being alerted.

The three victims — Swiss men aged 28, 43, and 52 — were hospitalised with stab wounds to the leg, neck, and thigh respectively. The two younger men were discharged or preparing to leave hospital by mid-afternoon, while the 52-year-old remained in hospital following emergency surgery. Eyewitnesses told local media that the attacker ran around the station area wielding a knife while those nearby screamed and fled. Several witnesses reported hearing the man shout "Allahu Akbar" — Arabic for "God is greatest" — before the attack. A school teacher was seen shielding a group of passing schoolchildren during the incident.

The suspect had a history known to authorities. He first came to police attention in 2015 for distributing Islamic State (IS) propaganda, and his two brothers had also been monitored in the past; all three are believed to have been radicalised at a mosque that has since been shut down by authorities. The suspect had reportedly spent much of the past two years in Turkey before recently returning to Switzerland. Earlier in the week, he had presented himself at a police station making incoherent statements and was taken to a psychiatric facility. He was discharged on Wednesday after a doctor determined he no longer posed a danger to himself or others.

Canton Zurich's security director Mario Fehr said it was "clear from the scene that the motive for this act must be sought in the realm of radicalisation and extremism", calling it "an evil act of terror". Swiss President Guy Parmelin said he was "shocked by the terrorist attack" and expressed wishes for the victims' swift recovery. Switzerland's Islamic Central Council strongly condemned the attack, stating that IS "is not an Islamic movement, but a perverse terrorist sect whose sole aim is to sow discord, murder innocent people and damage the reputation of Muslims worldwide".

The attack raises serious questions about the coordination between psychiatric services and security authorities when individuals with known extremist histories come to official attention. Investigators believe the suspect acted alone, and the station, which was cordoned off in the immediate aftermath, has since reopened.