A 17-year-old male has been arrested in connection to a stabbing incident in Southport, a seaside town in North West England, police said on Monday.
Merseyside Police had declared a "major incident" after the stabbing at a children's dance and yoga workshop that resulted in multiple casualties.
In a swift response, police apprehended the suspect and seized a knife believed to be used in the incident.
"At this early stage, enquiries are ongoing to establish the motive for this tragic incident and we would urge people not to speculate while the investigation is ongoing," police said.
"We can also confirm that the incident is not currently being treated as terror-related and we are not looking for anyone else in connection with the incident."
The BBC said eight people were stabbed and taken to the Alder Hey Children's Hospital.
British Prime Minister Keir Starmer described the incident "horrendous and deeply shocking."
"My thoughts are with all those affected. I would like to thank the police and emergency services for their swift response. I am being kept updated as the situation develops," he said on X.
UK Home Secretary Yvette Cooper said on X that she is "deeply concerned at the very serious incident in Southport."
"All my thoughts are with the families & loved ones of those affected. I have spoken to the Merseyside Police & Crime Commissioner to convey full support to the police & thanks to the emergency services responding," she added.