Three people have died and three others have been seriously injured after a stabbing in the UK, police confirmed.
A 25-year-old man from Reading has been arrested on suspicion of murder after being detained at the scene.
The attack happened at Forbury Gardens at about 7pm local time where several people were stabbed.
Police are not currently treating the incident as terror-related, but counter terrorism officers were called.
Security sources have told the BBC a man arrested at the scene is thought to be Libyan.
One eyewitness told the BBC he saw a man move from group to group stabbing people in the park.
There were reports that a police officer “rugby tackled” a suspect to the ground, according to the Sunday Mirror.
Detective Chief Superintendent Ian Hunter, from Thames Valley Police, said police are not looking for any other people in connection with the attack.
He added: “This is not currently being treated as a terrorism incident, however officers are keeping an open mind as to the motivation for the incident and are being supported by colleagues from Counter Terrorism Policing South East.”
Police have asked anyone with mobile phone footage of the attack to come forward.
But people have been urged not to share videos and photos online “out of respect for the victims’ families” after footage was circulated on social media.
Thames Valley Police said the incident was not connected to an earlier Black Lives Matter (BLM) protest in the park.
About a dozen armed police officers carrying shields were later seen entering a block of flats in Basingstoke Road in Reading at around 11pm local time.
Prime Minister Boris Johnson said his “thoughts are with all of those affected by the appalling incident in Reading”.
“My thanks to the emergency services on the scene,” he added.
Laurence Wort, 20, who was visiting Reading for the day on Friday, told the BBC he was about 10m away from the attack.
“A man walked along the path opposite where we were walking past a group of eight to 10 men, before darting to the left and going to stab three people in the first group.
“Changing direction, he runs towards us and then when we realises he’s not going to catch us, he turned back and went for another group that hadn’t realised what was happening yet, and he managed to stab someone in the second group,” Wort said.
Home Secretary Priti Patel tweeted to say she was “deeply concerned” at the incident.