A teenager is in custody suspected of attacking several people with a knife early on Monday in the coastal town of Southport in northwest England, near Liverpool.

Three children died of their wounds, and eight other children were injured, five of them critically, police said. Two adults were also in critical condition, police added. 

Merseyside Police said in a statement that the suspect was a 17-year-old from the nearby village of Banks, that he had been arrested and "will be questioned about the incident." 

Police also said the attack was not being treated as terror-related and that they were not seeking anyone else in connection with the crime.

They said investigations were ongoing and it was too soon to comment on a motive. 

"We would urge people not to speculate while the investigation is ongoing," police said.

What we know about the attack so far

A witness said they saw children running from a local community center that was holding a Taylor Swift-themed dance and yoga event for children. 

The North West Ambulance Service initially said its medics treated eight people and took some of them to local children's hospitals.

Police later said that two children had died as a result of the attack, and that a further nine children and two adults were injured.

Police said they were called to a property just before noon local time to reports of a stabbing, initially describing the attack as a "major incident."

Swift said she was "completely in shock" and still absorbing "the horror" of the event.

"These were just little kids at a dance class," the star wrote on Instagram. "I am at a complete loss for how to ever convey my sympathies to these families."

Prime Minister Keir Starmer called the attack "horrendous and deeply shocking." 

msh/wmr (AFP, AP, dpa, Reuters)