Bloodied children ran screaming from a dance and yoga class “like a scene from a horror movie” to escape a teenager’s savage knife attack that killed two children and wounded 11 other people Monday in northwest England, police and witnesses said.

A 17-year-old male was 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.

Nine children were among the wounded — six of them in critical condition. 

Two adults were also left in critical condition, police said.

“We believe the adults who were injured were bravely trying to protect the children who were being attacked,” Merseyside Police Chief Constable Serena Kennedy said.

The attack was the latest amid a recent rise in knife crime in the U.K. that has stoked anxieties and led to calls for the government to do more to clamp down on bladed weapons.

The Taylor Swift-themed workshop was held on the first week of school vacation for children aged about six 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 business that hosts everything from pregnancy workshops and meditation sessions to women’s bootcamps.

“They were in the road, running from the nursery,” said Bare Varathan, who owns a shop nearby. “They had been stabbed here, here, here, everywhere,” he said, indicating the neck, back and chest. 

‘Horrendous and deeply shocking’

British Prime Minister Keir Starmer called the attack “horrendous and deeply shocking.”

Police were called shortly before noon to a street where several small businesses are located behind rows of brick houses in Southport, a city of about 100,000.

The first officers who arrived were shocked to find so many casualties from the “ferocious attack,” most of them children with serious injuries, Kennedy said.

WATCH | Deadly knife attack stuns English seaside town: 

Stabbing attack kills 2 children in U.K.

Two children were killed and nine others injured in a stabbing attack at a Taylor Swift-themed dance class in northern England.

Colin Parry, an auto body shop owner, said most of the victims appeared to be young girls.

“The mothers are coming here now and screaming,” Parry said. “It is like a scene from a horror movie…. It’s like something from America, not like sunny Southport.”

The suspect, who has not been identified, lived in a village about eight kilometres from the site of the attack, police said. He was originally from Cardiff, Wales.