A third child died Tuesday from a mass stabbing at a Taylor Swift-themed dance event in northern England that Prime Minister Keir Starmer said "touches a nerve" with the whole country.
Starmer was among a stream of people to pay tribute at the site of Monday's knife attack in Southport, near Liverpool, that left five children and two adults with critical wounds. Three other children were hurt.
Laying flowers with hundreds of other wreaths, Starmer thanked emergency workers who responded to the stabbing spree and said: "I came here to pay my respects to the victims and families who are going through raw pain and grief that most of us can't imagine -- I can't imagine, as a dad myself."
Nine-year-old Alice Dasilva Aguiar died in hospital early Tuesday, police said. Bebe King aged six and Elsie Dot Stancombe aged seven were the two who died Monday.
A vigil for the victims was to be held in the town on Tuesday.
Police said the two wounded adults had been trying to protect the children. Tributes have already been paid to the bravery of dance and yoga teacher Leanne Lucas, who was among the victims.
A 17-year-old youth from a nearby village arrested shortly after the killings remained in custody, police added, without giving details of his identity.
They have only said that the attack was not considered "terror-related" and that noone else was being sought. Interior minister Yvette Cooper said police were pursuing "every single avenue".
US pop star Swift said she was "completely in shock" over "the loss of life and innocence, and the horrendous trauma inflicted on everyone".
"These were just little kids at a dance class. I am at a complete loss for how to ever convey my sympathies to these families," she added on Instagram.
- Town in mourning -
Aguiar was the daughter of Portuguese parents from Madeira. "Her parents are in a state of shock," Portugal's communities minister Jose Cesario told AFP.
Her family said in a tribute, "keep smiling and dancing like you love to do our princess, like we said before to you, you're always our princess and no one would change that."
Bebe King's family said, "no words can describe the devastation that has hit our family as try to deal with the loss of our little girl Bebe."
Residents of the seaside town said they were struggling to come to terms with the deaths.
"The town is in shock and in mourning", local MP Patrick Hurley told AFP, calling it the "most horrific atrocity that Southport has experienced in living memory".
It is a "very small town, a close-knit community and everybody will be intimately affected by this", he added.
"I just cannot believe that it happened so close to home," resident Leanne Hassan told reporters.
Hassan's daughter was at a nearby nursery which was locked down after the attack. Her daughter was safe, "but unfortunately that's not the reality for a lot of parents waking up today," she added.
Local business owner Colin Parry recounted to UK media how he saw "about 10 kids go running past him, all bleeding".
"One of them collapsed on the floor outside the neighbour next door," he told the Press Association news agency.
- 'Utterly horrific' -
The teenager arrested on suspicion of murder and attempted murder is from the neighbouring village of Banks but was born in Cardiff, according to police.
His identity has not been revealed. Police said a name shared on social media was "incorrect and we would urge people not to speculate on details of the incident while the investigation is ongoing."
Witnesses told UK media the attacker arrived at the scene in a taxi on Monday morning and entered the venue wearing a mask.
Armed officers detained the suspect later and seized a knife.
While such attacks are rare, Monday's incident evoked memories of a school massacre in the Scottish town of Dunblane in 1996, which claimed the lives of 16 pupils and their teacher in Britain's worst mass shooting.
King Charles III offered his "most heartfelt condolences, prayers and deepest sympathies" following the "utterly horrific" incident.
Heir to the throne, Prince William, and his wife Catherine said "as parents, we cannot begin to imagine what the families, friends and loved ones of those killed and injured in Southport today are going through".
By Roland Lloyd Parry With Akshata Kapoor In London