British police said Sunday they are treating a stabbing rampage in a park that killed three people as a terrorist attack.
Dean Haydon, the U.K.'s coordinator of counterterrorism policing, said counterterror detectives were taking over the investigation into the attack in the town of Reading, west of London. Police had earlier said they were keeping an open mind about the motive.
Three people were killed and three others seriously wounded in the stabbing attack in Reading's Forbury Gardens Park on Saturday evening. The Thames Valley Police force said officers arrested a 25-year-old local man at the scene 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.
The attack came out of the blue on a sunny summer evening in Forbury Gardens park in Reading, a town of 200,000 residents 40 miles (64 kilometers) west of London.
Prime Minister Boris Johnson was being briefed on developments. His office said Johnson had met security officials, police and senior ministers on Sunday morning for an update on the investigation.
Health Secretary Matt Hancock said the government was "closely monitoring the situation."
Police officers patrolled cordons on the roads leading to the park on Sunday, and blue-and-white tents were erected near the site of the attack. Overnight, heavily armed officers entered an apartment about a mile away, and a loud bang was heard.
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Personal trainer Lawrence Wort said the park in Reading was full of groups socializing on the grass Saturday 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.
The incident came hours after a Black Lives Matter demonstration at Forbury Gardens, but police said there was no connection between the attack and the protest.
Britain has been hit by several terror attacks in recent years, including a suicide bombing at an Ariana Grande concert in Manchester in 2017 that killed 22 people and two deadly vehicle and knife attacks in London the same year.
Britain's official terrorism threat level stands at "substantial," the middle level on a five-rung scale, meaning an attack is likely.
Lawless reported from London.