UPDATE at 11:11 ET: According to French prosecutors, the teacher who claimed to have been attacked by a masked assailant invented the story.
A pre-school teacher in the Paris suburb of Aubervilliers was attacked Monday morning in a classroom by a man who reportedly referred to Islamic State (ISIS) during the incident.
The teacher was attacked by the masked assailant with a box-cutter and scissors while preparing their classroom for the day, according to France 3. No children were present at the time.
"C'est Daech, c'est un avertissement," the attacker is reported to have said during the attack, meaning "It's Daesh (or ISIS), it's a warning". Anti-terrorism police are investigating the incident.
The assailant, who fled the scene on foot, remains at large and the motive for the attack is unclear, authorities said. French media reports said the teacher did not suffer any life-threatening injuries.
Anti-terrorism investigators are looking into the incident, Paris prosecutor's office spokeswoman Agnes Thibault-Lecuivre said.
Education Minister Najat Vallaud-Belkacem also went to the school, and promised to ensure security at schools around the country.
"It's an act of great gravity," she said. "It is inadmissible."
Tout mon soutien à l'enseignant agressé dans une école d'Aubervilliers et à l'ensemble des équipes. Nous sommes à leurs côtés.— Najat Belkacem (@najatvb) December 14, 2015
The incident comes as France remains under a state of emergency after Nov. 13 attacks by Islamic State-linked extremists that killed 130 people. Last week, a man carried out a knife attack in a London Underground station, which is being treated by police as a terrorist incident.
Additional reporting by The Associated Press.