The children were attending a Taylor Swift-themed dance class in Southport near Liverpool at the time of the incident.
A 9-year-old girl wounded in a stabbing attack at a Taylor Swift-themed dance and yoga class in northwestern England has died, bringing the death toll to three, as police questioned a 17-year-old suspect arrested minutes after the incident.
Merseyside Police said the other fatalities were girls aged 6 and 7.
Eight children and two adults remain hospitalised after the attack in Southport. Both adults and five of the children are said to be in critical condition.
A 17-year-old male has been arrested on suspicion of murder and attempted murder in the stabbing in Southport, a seaside town near Liverpool, Merseyside Police said. The motive was not clear, but police said detectives were not treating the attack as terror-related.
Two wounded adults who tried to shield the pupils were also in critical condition, police said.
The workshop was held on the first week of the school holidays for children aged about 6 to 11. The two-hour session was led by two women - a yoga instructor and a dance instructor - according to an online listing.
Witnesses described hearing blood-curdling screams and seeing children covered in blood emerging from the event.
Prime Minister Keir Starmer called the attack “horrendous and deeply shocking.” King Charles III sent his “condolences, prayers and deepest sympathies” to those affected by the “utterly horrific incident.”
The suspect, who has not been identified, lived in a village about 8 kilometres from the site of the attack, police said. He was originally from Cardiff.
Ryan Carney, who lives with his mother in the street, said his mother saw emergency workers carrying children “covered in red, covered in blood. She said she could see the stab wounds in the backs of the children.”
“All this stuff never really happens around here,” he said. “You hear of it, stabbings and stuff like that in major cities, your Manchesters, your Londons. This is sunny Southport. That’s what people call it. The sun’s out. It’s a lovely place to be.”
Singer Taylor Swift said she was “completely in shock” and still taking in “the horror” of the attack on the dance class inspired by her music.
“These were just little kids at a dance class," she wrote on her Instagram story, “I am at a complete loss for how to ever convey my sympathies to these families.”