The fatal stabbing of a teacher by a Chechen-origin man and wounding of three others at a French school on Friday have triggered a terror alert in France and mobilization of 7,000 troops to secure the country.

The knife attack took place in the northeastern town of Arras, home to large Jewish and Muslim populations.

Police arrested the suspected attacker, Mohammed Moguchkov, who had cried the Arabic phrase "Allahu akbar!" (God is greatest), according to the preliminary investigation.

The victim was stabbed in the throat and chest. A school security guard was stabbed multiple times and is fighting for his life, while a teacher was in a less serious condition, a police source said.

A cleaner was also hurt, according to anti-terror prosecutor Jean-Francois Ricard.

No pupils at the school were hurt, another police source said.

A separate "attempted attack" in another region had been foiled by security forces.

According to the interior ministry, a "radicalized" man carrying a prohibited weapon was arrested leaving a prayer hall in the Yvelines region of Paris.

Authorities have suggested a probable link to the ongoing violence in the Middle East, with President Emmanuel Macron denouncing the incident as an act of "Islamist terror."

"This school was struck by the barbarity of Islamist terrorism," Macron said after visiting the school, adding that the victim had "probably saved many lives" with his courage in blocking the attacker.

The Elysee presidential palace said the troops will be fully deployed by Monday.

Other members of the Moguchkov's family were also arrested on Friday for investigation.

The militant group Hamas that governs Gaza Strip on Friday called on Muslims around the world to attack Jews amid the Israel military's bombardment of the Palestinian enclave in retaliation for the killing of some 1,300 civilians in Israel by its followers last Saturday.

WITH AFP