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| Emergency services were pictured at the scene in the aftermath of the attack |
A man has been arrested on suspicion
of murder after a US citizen was killed and five other people were
injured in a knife attack in central London.
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| A forensics tent was put up next to the park in Russell Square which is a busy part of central London, with many hotels and the British Museum nearby |
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- Latest updates on Russell Square stabbings
- What we know so far about the attack
- At the scene: 'We saw a woman lying in the street'
The Met Police's assistant commissioner for specialist operations, Mark Rowley, said the investigation was increasingly pointing to the attack being "triggered by mental health issues".
He had earlier said the force was considering terrorism as a line of inquiry. Mr Rowley, Britain's most senior counter-terrorism officer, told a press conference it had been necessary to consider "all possibilities" following recent terror attacks across Europe.
Armed police were called to the square shortly after 22:30 BST on Wednesday after receiving reports of a man attacking people with a knife.
They arrived within six minutes and chased the suspect, who eyewitnesses said had blood on his hands. They said police ordered him to stand still but he kept running. He was then Tasered by officers.