ZURICH (AFP) - Ten people were arrested in an anti-terror operation in France and Switzerland on Tuesday (Nov 7), including a Swiss man linked to a foiled knife attack by a French teenager, sources close to the probe said.

A 27-year-old man arrested in Switzerland was in contact with a 14-year-old French boy who was "about to carry out the attack", one of the sources said.

The teenager was arrested in the Paris region on June 20 and charged by an anti-terror judge, the sources said.

A photo of the boy holding a paper vowing his allegiance to the Islamic State in Iraq and Syria (ISIS) group was found on social media, they added.

Nine suspects were arrested in southern France and the Paris region and were aged between 18 and 65, the sources said.

The suspects exchanged "disturbing remarks" on the Telegram encrypted messaging app, they said, adding that investigators were seeking to "determine what they were plotting".