A history teacher who opened a discussion with students on caricatures of Islam's Prophet Muhammad was decapitated in a French street on Friday and police have shot the suspected killer dead, a police official said.
He has been identified as 47-year-old Samuel Paty, a history and geography teacher.
The French anti-terrorism prosecutor has opened an investigation into the slaying for murder with a suspected terrorist motive, the prosecutor's office said. The gruesome incident occurred in the town of Eragny, in the Val d'Oise region northwest of Paris.
A police official said the suspect, armed with a knife and an airsoft gun was shot to death by police about 600 meters (yards) from where the male teacher was killed.
The teacher had been threatened after opening a discussion the debate, the police official told The Associated Press.
The suspect shot dead by police was an 18-year-old Chechen, police said.
France's anti-terrorism prosecutor's office said that authorities investigating the horrific killing have also arrested nine suspects, including the grandparents, parents, and 17-year-old brother of the attacker.
The teacher had discussed caricatures of the Prophet with his class, authorities said.
According to French newspaper Le Monde, some Muslim parents complained to the school about the slain teacher's decision to use one or more of the cartoons as part of a discussion about the Charlie Hebdo attacks, CNN reported.
Chechnya is a predominantly Muslim Russian republic in the North Caucasus. Two wars in the 1990s triggered a wave of emigration, with many Chechens heading for western Europe.
France has seen occasional violence involving its Chechen community in recent months, believed linked to local criminal activity and score-settling.
A police official said the suspect in Friday's attack armed was shot dead about 600 meters (yards) from where the teacher was killed. He was armed with a knife and an airsoft gun - which fires plastic pellets - and police opened fire after he failed to respond to orders to put down his arms, and acted in a threatening manner.
French President Emmanuel Macron on Friday called the killing of the teacher near Paris as a "terrorist attack".
"Our compatriot was killed for teaching, for teaching children freedom of speech, freedom to believe, or not to believe. Our compatriot was the victim of a terrorist attack," Macron, who arrived at the scene on Friday evening, said, as quoted by Sputnik.
Education Minister Jean-Michel Blanquer also condemned the incident and called it an "attack on France".
"Tonight the [French] republic was attacked with the heinous murder of one of its servants, a teacher. Tonight I think about him, about his family. Our unity and solidarity are the only answers to the cruelty of Islamic terrorism. We will fight back," Blanquer tweeted, as quoted by Sputnik.
The teacher had received threats after showing controversial cartoons of Prophet Muhammad to his pupils, French media reported.
French authorities would respond to the killing of a teacher near Paris in a "most decisive way", Prime Minister Jean Castex said on Saturday.
"The state, in solidarity with teachers, will react in the most decisive way so that the republic and its citizens live freely! We will never give up. Never," Castex wrote on Twitter.
Interior Minister Gerald Darmamin said on Twitter that he was "keeping himself directly informed" of the situation "from the crisis room (he) had opened, in liaison with the President of the Republic and the Prime Minister." Education Minister Jean-Michel Blanquer described the attack as a "despicable assassination of one of its servants, a teacher," and said his thoughts were with the family of the victim.
It was the second terrorism-related incident since the opening of an ongoing trial on the newsroom massacre in Jan 2015 at the satirical newspaper Charlie Hebdo.