Several children, some in pushchairs and between 22 months and three years of age, were injured on Thursday in a mass stabbing in Annecy in the French Alps.
A man armed with a knife attacked four children and two adults at 9.45am local time as the children were playing in a park near the lake in the town.
A local prosecutor confirmed that the suspect did not appear to have a "terrorist motive".
Among the injured are a 22 month-old child, two aged two and a three-year-old. Two of them are in a life-threatening condition.
One adult also sustained life-threatening injuries.
One of the injured children is a British citizen. Another young victim is Dutch, the local prosecutor said. Both are tourists.
"These are very small children who were very seriously injured. As a parent and citizen, we are already very shocked," Prime Minister Elisabeth Borne said on Thursday afternoon at a press conference in Annecy.
The suspect is a 31-year-old Syrian citizen who was granted refugee status in Sweden 10 years ago. He applied for asylum in France recently. The application is still pending.
On Thursday, the prosecutor in Annecy confirmed that the suspect was of "no fixed abode" and did not appear to have a "terrorist motive".
"The motive remains to be determined," said Line Bonnet-Mathis.
Reports said he is married with a three-year-old child and arrived in France in late 2022.
When asked if there would be anger about the suspect's "migration journey", Ms Borne said "solidarity must come first".
According to reports, the suspect is married to a Swedish woman, from whom he separated eight months ago. He is said to have been studying to be a nurse.
He claimed to be Christian and was wearing a cross when he was arrested.
In a video seen by AFP and confirmed by a source close to the case, the attacker can twice be heard saying "in the name of Jesus Christ" in English.
The attack has shocked France, with the French President Emmanuel Macron calling it an act of "absolute cowardice".
"Children and one adult are between life and death. The nation is in shock," Mr Macron said.
In Paris, politicians interrupted a debate to observe a moment of silence for the injured.
Annecy, a scenic town in the French Alps, is close to the border with Switzerland.
The attack took place at Le Paquiet park, a usually tranquil place popular with tourists for its stunning views of Lake Annecy and the mountains.
Video apparently of the attack was posted on social media, showing a man in dark glasses with a blue scarf covering his head brandishing a knife as people screamed for help.
In the horrific scenes, he first circled the playground, slashing at a bystander, and then clambered over its barriers to attack people and children inside. He appeared to stab one child in a stroller repeatedly.
He slashed at a man carrying rucksacks who tried to approach him, apparently trying to stop the attack.
He was later shot by police near the banks of the lake.
One man he tried to attack pursued him, using his rucksack as protection.
At least one child involved in the attack was in a pushchair and some appeared to be very young.
A man who spoke to broadcaster BFM TV said he saw first responders working on “little bodies, three or four years old, perhaps”.
"He jumped [in the playground], started shouting and then went towards the strollers, repeatedly hitting the little ones with a knife," another witness, who gave his name as Ferdinand, told the network.
Another witness, Malo, told a television channel that the man attacked the children before the old man and was "shouting, but it wasn't really comprehensible".
"Mothers were crying, everybody was running," George, the owner of a nearby restaurant, told BFM TV.
An ice-cream seller who works in the waterside park said he had seen the attacker there several days previously, looking out at the lake ringed by mountains.
"It's a place where babysitters and parents take young children to play. I often see around 15 toddlers there in the morning, and the atmosphere is fantastic," said Yohan, who works at an ice-cream parlour opposite the park.
Annecy knife attack - in pictures
Former Liverpool FC footballer Anthony Le Tallec witnessed part of the attack, describing the scene in a story on Instagram.
He said he was running by the lake and saw people rushing towards him telling him to flee because there was a knifeman attacking children.
Speaking in French, he said the suspect then appeared in front of him, tailed by police officers.
"He came near me, so I moved, I moved away,” he said.
“I see him go to towards a grandma and a grandpa, and he attacked the grandpa."
Le Tallec added: "I said to the cops: 'Shoot him! Kill him!' He attacked once, twice and then they started to shoot him."
Le Tallec said he continued his run along the lake, and spotted the children who were injured in the attack. “It’s unfortunate but it’s crazy to have this in Annecy," he said.
Local police said a second adult was injured and was being treated with the others in a hospital.
The children were reportedly on a school trip.
Police said two of the children are in a life-threatening condition, while one adult suffered life-threatening wounds. The other children were "slightly hurt", they said.
BFM TV showed footage of several policemen overpowering an individual in a park.
Counter-extremism experts called for calm after a surge in anti-Syria and anti-refugee sentiment on social media.
Speaking to The National, Sofia Koller, senior research analyst at the Counter Extremism Project, said she was concerned the incident could led to more than rhetoric.
“It's very early to speak about it being a terror attack because the motivation is not clear yet," she said.
“Some media and parts of the public are quick to judge when they see it was a foreign-looking man with a knife, and assume it was a terror attack.
”There are continuing debates and discussions in France and Europe on asylum seekers and immigration, Ms Koller said, speaking from Germany.
"So I think this attack really comes at the worst timing because the debate is quite present at the moment. So this attack might have an even higher impact on French society,” she said.
Interrupting a raucous debate about pension reform, parliament speaker Yael Braun-Pivet told MPs: "There are very young children in a critical state and I ask you to observe a minute of silence for them, for their families.
"We hope that the consequences of this extremely serious attack are not consequences that will send the country into mourning," she added.
France's Interior Minister Gerald Darmanin said in a tweet that police had detained the attacker.
“Several people including children have been injured by an individual armed with a knife in a square in Annecy,” he tweeted.
UK Foreign Secretary James Cleverly confirmed one of the victims is British.
"One of the ... children injured was a British national. We have already deployed British consular officials to ... support the family," he said at an Organisation for Economic Co-operation and Development (OECD) press conference in Paris.
"Our thoughts are with the victims and the families and we stand ready to support the French authorities in whichever way we can."
UK Prime Minister Rishi Sunak also sent his condolences to the victims and their families.
“The prime minister’s thoughts and sympathies will be with all those who have been affected,” a spokesman for Mr Sunak told reporters.
