A Swiss woman grabbed a woman by the neck and stabbed another in a department store in the southern Swiss city of Lugano on Tuesday, police said.
Ticino cantonal police said the attack was over and the suspect, a 28-year-old who lives in the area, was in custody.
One victim sustained serious but not life-threatening injuries and another was lightly injured.
Police said they had not ruled out terrorist motives but the case was still under investigation.