A knife attack by a woman on a shopper in a Swiss department store is being treated as a suspected terrorist incident.
The woman, who is Swiss, knifed a victim in the neck and grabbed another by the throat in a Lugano department store on Tuesday.
She was a known extremist who fell in love with a militant online and tried in vain to meet him in Syria, police said on Wednesday.
Federal prosecutors are calling the incident in the Italian-speaking southern canton of Ticino a suspected terrorist attack and taken charge of the investigation.
"Police investigations in 2017 revealed that the woman had formed a relationship via social media with a fighter from Syria," the Federal Office of Police tweeted.
Turkish authorities turned her back at the border into Syria when she tried to travel there to meet the man, and returned her to Switzerland at the time, it said.
"The woman was suffering from mental health problems at this time. After returning to Switzerland, she was admitted to a psychiatric clinic," Fedpol said. She had not come to the agency's attention in any terrorist-related investigation since 2017.
The suspect, a 28-year-old who lives in the area, was in custody after passers-by subdued her until police arrived.
One victim sustained serious but not life-threatening injuries and another was slightly injured.
Switzerland has so far been spared the kind of large-scale terrorist attacks that prompted France and Germany this month to push for tighter European Union borders, after suspected Islamist militants killed eight people in Paris, Nice and Vienna within a month.
But it has identified hundreds of residents deemed a threat and militants who have travelled to war zones.
Two men arrested in the town of Winterthur this month over possible links to an extremist shooting attack in Vienna that killed four people on November 2, visited the attacker in July.
In September, a man Swiss media called the "Emir of Winterthur" and described as a leading Islamist militant in Switzerland, was sentenced to 50 months in prison for ties to ISIS.
The same month, Switzerland suffered its first extremist attack on home soil since 2011 when a Portuguese man was murdered outside a kebab shop.
Federal prosecutors said the incident was still being investigated for a possible "terrorist motive". A Swiss-Turkish citizen was arrested. The suspect had just been released from prison and was known to the Federal Intelligence Service for at least three years.
Its annual intelligence report said the terrorist group is a “dominant force”, but also warned of the new threat posed by left-wing extremists, over concerns they are trying to take control of the Black Lives Matter movement.
The FIS raised concerns about Islamist terrorist groups in the country and the threat of returning fighters.
The terrorist threat in Switzerland has been at a heightened level since November 2015 and although ISIS is the predominant threat, the risk posed by Al Qaeda still persists, it said.