Macron holds security meeting after deadly school stabbing and mosque knife arrest

French authorities have opened anti-terror investigations after one person was killed and two others seriously injured in a knife attack at a school in the northeast town of Arras. 

Local police say a man armed with a knife killed a teacher and left two other people wounded in a high school in the town of almost 41,000 people on Friday morning. The attacker has since been arrested. 

The incident took place at the Gambetta high school, which is located in the town centre, and police say the attacker shouted "Allah Akbar" - God is great in Arabic.

He has been named as 18-year-old Mohammed Mogouchkov, a former student at the school of Chechen origin who was the subject of "active monitoring" by France's General Directorate of Internal Security DGSI. 

Mogouchkgov had been stopped and searched as recently as last week but was released as there was no reason to hold him, officials said. 

No high school student was injured in the attack, but a security guard and a teacher were gravely wounded after suffering several stab wounds. 

France's President Emmanuel Macron visited the school on Friday afternoon, and called on people to remain "united" and to "stand together" in the face of "the barbarity of Islamist terrorism." 

Speaking in the courtyard of a building near the school where Friday morning's deadly stabbing took place, Macron said "the choice is made not to give in to terror, not to let anything divide us." 

Later on Friday evening, Macron held an emergency meeting of his security cabinet in Paris. 

Senior government ministers, police, military and intelligence officials attended the meeting which came after a second security incident was confirmed. 

A 24-year-old man known to have been "radicalised" was arrested and placed in