At a dramatic press conference, Police Chief Serena Kennedy announced with great sorrow that she could confirm that two children had been killed in the attack. Eleven people were injured, and the situation is critical for six of them.
A 17-year-old has been arrested and detained for the deed.
The police describe how he came in from the street at lunchtime and began attacking the children, while the adults in the premises tried to protect them.
"Tried to protect the children"
A witness tells the news agency AP how bloody children came running from the event, where dance and yoga with a Taylor Swift theme were held for children aged six to eleven years.
Two adults are said to be among the seriously injured.
We believe that the adults who were injured with all their courage tried to protect the children who were attacked, said Serena Kennedy at her press conference.
I have difficulty imagining the pain and suffering that the families of the victims are going through.
British Prime Minister Keir Starmer said directly after the announcement that he – and the country – were in deep shock after the deed.
Our thoughts are with the victims, their families, friends, and the local community, said Starmer.
No terrorist suspicions
The police are not looking for any other perpetrators and describe the motive as unclear, but add that there are no suspicions of a terrorist-related crime.
A businessman near the premises believes he saw between six and seven girls with knife wounds.
It feels like something that happens in the USA, not here in sunny Southport, he says to BBC.
Quiet area
Even the British Home Secretary Yvette Cooper expressed sorrow and dismay over the attack, while praising the quick police response.
The alarm about the attack came just before 12 o'clock local time.
Southport, with around 100,000 inhabitants, is located on the coast outside Liverpool.
The place where the attack took place is described as a quiet residential area.