An attacker injured six children and one adult with a knife in a park in the eastern French town of Annecy on Thursday, leaving the nation "in shock," according to President Emmanuel Macron.
He described the attack as "absolutely cowardly," adding: "Our thoughts are with the victims and their families, as well as the rescue workers deployed."
Investigators see no indications so far hinting at a terrorism motive. Two of the children and one adult were in a life-threatening condition and two other children aged about 3 were slightly injured, the police told dpa on Thursday.
The suspected perpetrator was arrested. The Syrian had only been in France a few months and had no fixed abode. He had lived for a long time in Sweden, authorities said, but there was no history of violence or psychiatric problems.
Media reports said he had married a woman in Sweden and had a young child but that he had recently split from his wife.
The exact circumstances of the attack were unclear. The broadcaster BFMTV reported that several groups of children had been in the park near the famous Lake Annecy at the time of the incident.
Security forces were deployed quickly to the scene, France's Interior Minister Gérald Darmanin said on Twitter.
A British child is among the victims, Foreign Secretary James Cleverly was quoted as saying by PA Media.
Annecy public prosecutor Line Bonnet-Mathis said the attacker is still to be interrogated, adding that his motive remained unclear and that he was suspected of attempted murder.
The National Assembly interrupted its plenary debate in the morning for a minute's silence. Parliamentary President Yaël Braun-Pivet said: "We hope that the consequences of this very serious attack will not be consequences that lead the nation into mourning."
French Prime Minister Élisabeth Borne planned to go to the scene of the crime.