A man has been arrested after three people were injured in a stabbing attack at a train station in Switzerland, police said.

They said the three victims - Swiss nationals aged 28, 43 and 52 - were hospitalised after the attack at Winterthur train station.

The suspect, a 31-year-old Swiss man, used a bladed weapon and that the motive was under investigation, police added.

An eyewitness working in an office building nearby told a local newspaper he heard a man yell "Allahu Akbar" - meaning "God is greatest" in Arabic - at around 08:30 local time before attacking people with a knife.

A group of schoolchildren were passing through the area at a time and a school teacher was seen standing in front of them to protect them, according to local media.

Another eyewitness, a taxi driver, told Zurich-based daily Neue Zürcher Zeitung that a man had been walking around the station's underpass attacking people.

Photos published by Swiss news outlets show several areas around the station being cordoned off.