The suspect in a knife attack in which four toddlers and two pensioners were wounded in the southeastern French town of Annecy on Thursday has been placed in detention, the local prosecutor said on Saturday.

The suspect, a Syrian refugee born in 1991, is under formal investigation for attempted murder and resisting arrest with a weapon, the prosecutor said.

The injured are no longer in critical condition, Annecy Prosecutor Line Bonnet-Mathis told a news conference, adding that the four children were still in hospital.

The stabbing was the first violent attack targeting children since 2012, when gunman Mohamed Merah shot three Jewish children and one of their parents, and then three soldiers, in Toulouse in 2012.

The suspect has chosen not to speak while in police custody and when presented before judges, the prosecutor said. He was examined by a psychiatrist who considered that he was fit to be held in custody.

Drug and alcohol tests were negative.

"Presently it is premature to assess his motivations," Bonnet-Mathis said, reiterating that there was no indication yet that terrorism was the assailant's motivation.

The suspect was granted asylum in Sweden 10 years ago, having arrived from Turkey. The prosecutor said the man was believed to be married with a young child.

He entered France in October 2022, having travelled through Italy and Switzerland, she said, adding that he had no police record in France and was thought to be homeless.

His request for asylum in France was refused on the grounds that Sweden had already approved one. (Reuters)