A man on Friday decapitated a history teacher in France who had recently shown cartoons of the Prophet Mohammed in class, police said.
The attacker, whose identity has not been established, was shot by police as they tried to arrest him and later died of his injuries, they said, according to AFP.
The attacker shouted "Allahu Akbar" as police confronted him, a police source said.
French anti-terror prosecutors said they were treating the assault as "a murder linked to a terrorist organization" and related to a "criminal association with terrorists".
The attack occurred at around 5:00 p.m. local time on Friday near a school in Conflans Saint-Honorine, a northwestern suburb located some 30 kilometres (19 miles) from Paris.
According to a police source, the victim was a history teacher at a local middle school who recently discussed cartoons of the Prophet Mohammed in class.
According to a Reuters report, investigators are looking into allegations that the attacker, reportedly an 18-year-old of Chechen origin, had acted alone or had accomplices.
Police on Friday arrived at the scene after receiving a call about a suspicious individual loitering near the school, a police source said.
There they found the dead man and nearby sighted the suspect armed with a knife-like weapon, who threatened them as they tried to arrest him.
They opened fire and injured him severely, the source said. The man later died of his injuries, a judicial source said.
The scene was cordoned off and a bomb disposal unit dispatched because of the suspected presence of an explosive vest, the police source said.
Interior Minister Gerald Darmanin, who was on a visit to Morocco at the time of the attack, returned to Paris immediately after talking with President Emmanuel Macron, as well as Prime Minister Jean Castex, his office said.
France's parliament suspended Friday's debate after news of the decapitation, with session president Hugues Renson, visibly moved, calling the attack "abominable".
Education Minister Jean-Michel Blanquer tweeted, "The Republic is under attack", adding that "our unity and firmness are the only answers to the monstrosity that is Islamist terrorism."
In recent years, France has been hit by a number of attacks claimed by ISIS, the biggest one being the attack in November of 2015 in which 129 people were murdered.
The country has been under a heightened alert in recent years in the wake of the attacks.
Just last month, a 25-year-old man wounded two people in a meat cleaver attack in Paris. He was subsequently charged with "attempted murder with relation to a terrorist enterprise."
(Arutz Sheva’s North American desk is keeping you updated until the start of Shabbat in New York. The time posted automatically on all Arutz Sheva articles, however, is Israeli time.)