The suspect in the knife attack in the French alpine town of Annecy that left four children and two men injured is facing attempted murder charges, prosecutors say.

If convicted he faces a maximum sentence of life imprisonment.

Investigators are still trying to determine why the suspect -- who has been identified as a 31-year-old Syrian asylum-seeker -- carried out the attack, which took place in front of horrified onlookers at a playground on Thursday. Authorities say they have no indication it was terror-related.

On Saturday, "he was presented to the two investigating judges who charged him with these offenses. He did not wish to speak to the judges," Line Bonnet-Mathis, Annecy's Public Prosecutor said.

The man is said to be married, with one child, and arrived in France from Sweden in 2022. He was not previously known by French law enforcement.

Eyewitnesses on Thursday described the attacker entering the playground to target the children.

Some told officials that they heard the attacker "mention his wife and daughter and pronounce the name Jesus Christ," the prosecutor said.

French President Emmanuel Macron on Friday thanked, among others, a 24-year-old man dubbed the "bagpack hero," who confronted the perpetrator and swung his bag to fight him off.

The man, who identified himself only as Henri, told CNN affiliate BFMTV on Friday that it was "impossible to leave defenseless people to be attacked" in that way.

The six people wounded in the attack did not have any life threatening injuries and have been examined by a forensic doctor, according to the prosecutor, who added that the four children remain in hospital.

Two of the children are French, one is British and one Dutch.