Three people were killed and three seriously hurt in a summer-evening stabbing attack in a park in the English town of Reading.
Police say it’s “not currently” being treated as a terrorism-related offence and the motive remains unclear.
Thames Valley Police force said officers arrested a 25-year-old local man at the scene on suspicion of murder and they were not looking for anyone else.
“There is no intelligence to suggest that there is any further danger to the public,” said Detective Chief Superintendent Ian Hunter.
“This is not currently being treated as a terrorism incident; however, officers are keeping an open mind as to the motivation for the incident,” Hunter added.
He said detectives from the counter-terrorism unit were supporting the investigation.
British media had earlier reported that police suspected a terrorist motive and that the man arrested was Libyan. Police did confirm that or release the suspect’s name.
Prime Minister Boris Johnson said his “thoughts are with all of those affected by the appalling incident in Reading.”
The violence erupted around 1900 GMT as families and friends were enjoying a warm, sunny evening in the Forbury Gardens park in Reading, a town of about 200,000 residents 64 kilometres (40 miles) west of London.
Witnesses reported that police cars and helicopters descended on the park. Within minutes police had blocked off several roads, and two air ambulances landed nearby.
Personal trainer Lawrence Wort said the park was full of groups socialising on the grass when “one lone person walked through, suddenly shouted some unintelligible words and went around a large group of around 10, trying to stab them.”
“He stabbed three of them, severely in the neck, and under the arms, and then turned and started running towards me, and we turned and started running,” Wort said.
“When he realized that he couldn’t catch us, he tried to stab another group sat down. He got one person in the back of the neck and then when he realized everyone was starting to run, he ran out the park.”