Police officers at the scene of a knife attack at a railway station in Winterthur, Switzerland

A man armed with a knife injured three people at a train station in the Swiss city of Winterthur on Thursday in what authorities described as a “terrorist act” before being arrested by police.The attack occurred shortly before 8:30 a.m. local time. The suspect, a 31-year-old Swiss-Turkish dual citizen who lives in Winterthur, was taken into custody within five minutes of emergency services being alerted, police said.Regional police chief Marius Weyermann said the suspect had previously come to the attention of authorities in 2015 for spreading propaganda linked to the Islamic State group.Weyerman also said the man had recently been admitted to a psychiatric facility after calling emergency services and making “confused comments,” but was released Wednesday after doctors determined he was not a threat.Three Swiss men, aged 28, 43 and 52, were injured in the stabbing. Officials said two have been discharged or are expected to leave the hospital at the end of the day, while a third remains hospitalized after undergoing surgery for a thigh injury.Investigators believe the suspect acted alone.Zurich regional security officer Mario Fehr described the incident as “an evil act of terrorism”.Winterthur, located near Zurich in northeastern Switzerland, has a population of about 123,000 people.