British police declared on Sunday that a stabbing spree which occurred in Reading the previous night was a terrorist incident. A 25-year-old man has been arrested after three people died and another three sustained serious injuries. Counter-Terrorism officers are now taking over the investigation, Thames Valley Police said in a statement. Chief Constable John Campbell described the incident as truly tragic. Incidents of this nature are very rare, though I know that will be of little comfort to those involved and understand the concern that this incident will have caused amongst our local community, I would also ask that the public avoid speculation, he added. Police and other emergency services attended the scene in Forbury Gardens at around 19:00 BST on Saturday evening and quickly apprehended the suspect. Detective Chief Superintendent Ian Hunter, Head of Crime, said police were not looking for any other people in connection with the incident, adding there was no further danger to the public. Authorities added that video footage of the incident had been captured on mobile phones, urging people not to circulate it on social media and to use it to help the police instead. Thames Police initially ruled out the stabbing was terror-related, or that it was linked to a Black Lives Matter rally held in the park a few hours earlier. The area remains cordoned off and people are being urged to stay away. Reading Council leader Councillor Jason Brock said he was shocked and appalled by the horrific and senseless attack. Prime minister Boris Johnson sent his condolences to the families and friends of the victims. Home Secretary Priti Patel described the incident as a senseless attack, adding: My heart, prayers and thoughts are with all of those affected and to the people of Reading who will be deeply shocked and concerned by this terrible incident. I am in contact with police and will ensure they have all the support they need, she continued.